There are a few combos in the deck and for the purpose of simplicity, I will give examples with only one option for those combos that can have multiple and highlight the other options in the explanation.
The combo works like; with Tatyova, Retreat of Coralhelm, a not summoning sick Sakura-Tribe Scout and a bounce land in hand ; you use Sakura-Tribe Scout's tap ability to place the bounce land into play. This will trigger Tatyova, Retreat to Coralhelm, and the bounce land. You draw a card and gain a life off of Tatyova, untap your Sakura-Tribe Scout with the Retreat to Coralhelm, and bounce the bounce land itself with the bounce land trigger. This brings you back to where you started and you can rinse and repeat until you have drawn your deck or another win condition.
This combo has some variability with the bounce land and the tap ability creature. Bounce lands include; Simic Growth Chamber, Guildless Commons, Oboro, Palace in the Clouds, and Ghost Town. This combo will also work with with Oboro in play at the start because you can tap it for blue and use that to return it to hand instead of a bounce land etb trigger. This combo also works with Ghost Town but only on an opponents turn. You can use this to win with Laboratory Maniac on an opponents turn. Tap ability creatures include; Sakura-Tribe Scout, Llanowar Scout, and Walking Atlas.
This combo can also gain you mana by instead of playing a bounce land with your Sakura-Tribe Scout's ability you can play any other lands you have drawn through this combo. This still works because you will still untap your Sakura-Tribe Scout with Retreat to Coralhelm and draw your card off of Tatyova. This combo works best with the bounce land, but if you have a few lands in hand you can start the combo with Tatyova, Retreat to Coralhelm, and Sakura-Tribe Scout and go through the loupe until you hit a bounce land or stop drawing lands and wiff. With the high land count and other ramp pieces you are unlikely to wiff, but it has happened.
This combo works to draw your whole deck to win with Thassa's Oracle or Laboratory Maniac or draw Alter of Dementia to sacrifice Tatyova and play Scute Swarm and continue the combo for infinite Scutes Swarms and swing with Concordant Crossroads or Finale of Devastation. The nice part of this combo is while you are doing the combo and drawing your deck you are able to play non-bounce lands to also have a ton of mana to have a variety of ways to win once you have drawn your deck.
This combo works by having Tatyova, Trade Routes, and Lotus Cobra in play with Journey to the Oracle in hand. This combo will require you to have a bit going on specifically untapped lands and lands in hand before you are able to pull it off. The combo goes like play Journey to the Oracle
discard a card to return Journey to hand; put lands into play off Journey, draw off the Tatyova trigger, and make mana off of Lotus Cobra. Use the Trade Routes ability to return as many lands as you can to your hand and still be able to cast Journey to the Oracle
, play Journey and put the lands into play, draw more cards off Tatyova, and Produce more mana off of Lotus Cobra. Continuing this loupe will net you mana as your draw more lands with Tatyova.
Some alternatives for this combo revolve around how mana is produced . The alternatives to Lotus Cobra include Tireless Provisioner and a combo of Scute Swarm and Gaea's Cradle. Although more cards, the combo of Cradle and Scute Swarm makes this combo very easy as you can tap Cradle for lots of mana to return lands including Cradle and cast Journey to the Oracle while still netting mana.
This combo creates the same outcome as the Retreat to Coralhelm combo in generating essentially infinite mana and drawing your deck to win with Thassa'a Oracle, Laboratory Maniac, Scute Swarm, Craterhoof Behemoth, Finale of Devastation, and Aetherflux Reservoir.
This combo works with Tatyova, Kodama of the East Tree, and Tireless Provisioner in play with Simic Growth Chamber in hand for your land for turn. As you play the bounce land you get a trigger of Tatyova, tirless provisioner, and Kodama. You place them on the stack as Kodama, Tireless Provisioner, Bounce Land, and Tatyova on top. Working in reverse order you draw a card and gain a life, bounce your land to hand, and create a treasure token with Tireless Provisioner. This Token entering the battlefield triggers Kodama once again to put a 0 cmc permanent into play. With this trigger you play the bounce land once again and recreate the same stack as before. You can rinse and repeat this to once again draw your deck.
This plays the exact same way as the past combos were you now can play everything in your deck with infinite mana off of treasure tokens, life with Tatyova and Aetherflux Reservoir, and damage with Scute Swarm, Finale of Devastation, and Aetherflux Reservoir to win the game.