The basic gist is that you play ramp spells (Cultivate, Kodama's Reach, Explosive Vegetation etc.) and cards that make your creatures cheaper (Urza's Incubator, Herald's Horn etc.) and then start dropping big dinosaurs on the board and swing at your opponents faces. The most important creature is, of course, Gishath. It should be your number #1 priority to get on the board as it can, with little luck, flood your board with huge creatures in one turn and practically win you the game if no one has any answers. Gishath can also kill players with commander damage pretty quickly.
Now a bit about the card choices and cards you may wanna add to the deck. Creatures in this deck are pretty self-explanatory. Dinosaurs and a few non-Dinosaurs that somehow support them. If you wish, you can cut back on the dinosaurs and dino-supporters and play a bit more non-tribal creatures that help you bring out your big hitters faster, like Oracle of Mul Daya, Sakura-Tribe Elder, Courser of Kruphix and such. This of course makes Gishath not as reliable, so I chose not to play them and because I wanted to keep the deck as a (almost) pure dinosaur tribal. As for dinosaurs not included, stuff like Needletooth Raptor, Regal Behemoth, Cherished Hatchling and Cacophodon might fit in to the deck nicely. I'd stay away from Gigantosaurus though, as it's mana cost is pretty tricky for a 3-color deck. Also, if you run Huatli, Dinosaur Knight, you might want to consider playing Sun-Blessed Mount, which can tutor Huatli from your deck or graveyard.
The top performers, at least in my games, have been Kinjalli's Sunwing, Etali and Zacama. Kinjalli's Sunwing is excellent in keeping more aggressive decks in check while you ramp up and disrupting possible combos or effects that require tapping creatures. Zacama is basically 18 mana worth of value if you cast it. Be sure to tap every mana producing land you got before casting Zacama. This works especially well if you have some sort of mana doubling effect in play. For further shenanigans, if you pair this with some sort of effect that let's you return Zacama to your hand multiple times per turn (say Temur Sabertooth), you can easily generate infinite mana. Etali usually gets you at least two cards you can cast for free and free cards is never a bad thing. Remember that you can also leave the cards you don't want to cast in exile. With a little luck, you can get rid of your opponent's combo pieces, sweepers and other such nasties.
Sorceries in this deck are also pretty self-explanatory. Most of them are your everyday green ramp, with Rishkar's Expertise thrown in for card draw and cheating out cards with cmc 5 or less and Savage Stomp for cheap single target removal. If you want more ramp, I'd recommend Three Visits, Spoils of Victory and Nature's Lore as they work with duals and shock duals. For non-ramping sorceries, you might wanna consider cards like Harmonize, Life's Legacy and Momentous Fall for extra card draw or sweepers like Blasphemous Act and Wrath of God. Keep in mind that with such a creature heavy deck, your sweepers will likely harm you as much as your opponents. If you want to/need to play sweepers that won't likely kill your own creatures and work as Enrage triggerers, consider playing red cards like Anger of the Gods, Sweltering Suns and spells that deal X damage to all creatures so you can at least spare your beefiest creatures. Triumph of the Hordes is also an excellent wincon for this deck.
The instants in the deck are a mixture of single target removal, tutoring and board protection. The single target removal package is pretty basic; Path to Exile and Swords to Plowshares for creatures, Krosan Grip and Return to Dust for artifacts and enchantments. For more instant speed removal, stuff like Wear/Tear, Condemn and Beast Within are decent choices. Single target burn spells are not worthwhile, in my opinion. The tutoring package in this deck is unsurprisingly creature focused. Eladamri's Call tutors any creature to your hand for mere 2 mana and Congregation at Dawn is excellent with Gishath. Cast it before Gishath deals combat damage to guarantee at least three dinos off of Gishath's ability. For more instant speed tutoring, consider Worldly Tutor and Chord of Calling. Finally, the protection package. Heroic Intervention and Boros Charm are there to protect your creatures when your board is huge and someone wants to ruin your day by playing a sweeper. For added protection, consider adding Teferi's Protection, which not only protects your permanents, but also your life total.
As for the planeswalkers, Domri Rade is occasional card draw and in most cases removal, as your creatures are most likely the biggest on the board. If you can get the emblem out, you pretty much win. Huatli, Dinosaur Knight beefs up your dinos with +1/+1 counters and also acts as creature based removal. Huatli, Warrior Poet on the other hand produces 3/3 trample dinosaur tokens and can basically cast Aurelia's Fury with her last ability, or you can just nuke something big off the board, if you have enough loyalty on her. The third Huatli (G/W one) is not worth playing. Her first ability does absolutely nothing, her -1 is very dependent on your board. If you have say two big creatures on board, she only gives +2/+2 to target creature, which is basically nothing in EDH. The final ability is overpriced, card draw is nice but -8 seems a bit too much. For additional planeswalkers, Samut, the Tested, Garruk, Primal Hunter, Xenagos, the Reveler and Vivien Reid might be worth your time.
The artifact package is very simple. Herald's Horn and Urza's Incubator for making dinosaurs cheaper to cast and Sol Ring, well, because it's Sol Ring. All EDH decks are required to play it by law. In addition to these, you can try to fit in the three signets (Boros, Gruul and Selesnya ones) and maybe Mana Vault/Mana Crypt type of mana rock. Bear in mind that you shouldn't require too much mana rocks as you already have plenty of ramp spells and effects that make your stuff cheaper. Coat of Arms is also a pretty decent addition, but make sure your meta doesn't have too many other tribal decks, as Coat of Arms' effect is global. Vanquisher's Banner is also decent, while it gives only +1/+1, it let's you draw a card every time you play a creature of the chosen tribe. I feel that this deck doesn't really need Lightning Greaves or Swiftfoot Boots, as Gishath already has haste. Sure hexproof/shroud is nice, but I feel it's not really necessary as most of the time, at least in my meta, Gishath is not killed by single target removal but by sweepers. Vedalken Orrery is also a great addition so that you can flash in your big beaters at the end of your opponent's turns.
The enchantment package is a bit of a mixed bag. Mirari's Wake and Zendikar Resurgent are there to double my mana, Pyrohemia functions as a controllable sweeper and is very handy for triggering your Enrages, Sunbird's Invocation is yet again a card that can cheat out stuff for free and Growing Rites of Itlimoc may let you draw a card, but most importantly, it shouldn't be too hard to transform it to a better version of Gaea's Cradle. Other enchantments worthy of adding are haste effects such as Fervor, Fires of Yavimaya and Concordant Crossroads, stuff that let's you draw more cards like Greater Good and Elemental Bond and enchantments that deals damage when your creatures enter the battlefield like Warstorm Surge. Ascetism, Survival of the Fittest and Sylvan Library are also good additions.
The mana base is a pretty basic one with duals, shock duals and on-color fetches. For utility, I play Strip Mine, Kessig Wolf Run, Homeward Path and Gavony Township. Other useful utility lands would be Rogue's Passage, Sunhome, Fortress of the Legion, Scavenger Grounds for graveyard hate and Winding Canyons, which acts as a 2 mana temporary Vedalken Orrery for your creature spells.
Now, about playing the deck. Your starting hand should ideally contain about three lands, a ramp spell, a cheap mana rock or a discount effect and something to deter early aggression (cheaper creatures, removal etc.). You don't need to keep any of the higher cost creatures in your starting hand as you should have plenty of ways to cheat them in to play later straight from your deck. The most important thing is to get Gishath on to the field ASAP, so your starting hand should reflect that. Once you get your general out, start swinging! Try to build a board big enough that whatever creatures your opponents play are dwarfed by your dinosaur army. At this point, when your opponents creatures are too puny to be considered nothing more than mere annoyances, sweepers become your biggest threat. To deal with them, save your Boros Charms, Heroic Interventions and Teferi's Protections or whatever protection cards you're playing , it's usually not worth playing them to save one or two creatures, unless one of those creatures is Gishath and you can't cast it again next turn. Remember that you don't have to put any creatures in to play with Gishath's ability if you suspect that someone is holding a board sweeper. If and when the board inevitably blows up at some point (if it doesn't, I hope your opponents enjoy getting stomped in the face), you start rebuilding. The ramp and discount effects should make it relatively easy to cast Gishath or other bigger threats after a board wipe. This is where additional mana rocks would come in handy too, if you choose to play them. The biggest hurdles for this deck are board wipes, tax effects (Propaganda-like effects), effects that make your creatures come in to play tapped (Blind Obedience and friends) and huge flying creatures (most creatures that Kaalia decks play), as this deck doesn't have that many fliers of it's own.