You play enchantments and then sack those enchantments to get creatures. That's simple. Some of the card choices aren't as simple.

The Terror of the Peaks is in there, partially because it goes infinite with Sporeweb Weaver and Linvala to make infinite Saprolings and gain infinite life. It can't be cast other ways, so if you draw it, that's bad. I used to have Dryad of the Ilysian Grove to have a chance of casting it, but that came up even more rarely than the combo, and I would often just search Dryad for its big booty, so I replaced Dryad with Egon, God of Death. Egon could probably be replaced with Lovestruck Beast as a big, dumb blocker when you need it, but that would break the streak of having no Eldraine cards. As for replacing Terror of the Peaks, the top replacements I considered were Keruga, Nethroi, or Obosh, but I don't really like any of them particularly. Maybe just a second Gargaroth.

Point being you can swap out a lot of creatures and make it work how you like it.

As for play pattern, you usually play manas 1-3 by whatever's in your hand, prioritizing Omen of the Sea last, and Ranger Class or Wolfwillow based on how aggro the matchup is. When you get down Enigmatic Incarnation, if it's early game, the first get is often Lanowar Visionary for the guaranteed value and replacing Wolfwillow's ramp if you sacked it. If you're against mono-red and sometimes dragons, Sporeweb Weaver is a house or Barrin if you need to affect the board (Anax). I usually wait to get Setessan Champion or Lurrus for when I can flash out Omen of the Sea (Lurrus allows you to cast the Omen in the same end step that you sacked the Omen to search Lurrus). Lurrus is also great bait if you want to protect some other creature or get your opponent to stall themselves killing it. 

The five drops you get for whatever the situation is at that point: Gargaroth against aggro, Iymrity against removal, Mind Flayer against removal light creature decks, etc. There is a nice mode on Yorion where searching it at the end of the turn lets your board dodge sweepers like Shadow's Verdict or Ugin, if you can guess it's coming. You're often searching the 5 drops by sacking second Incarnations (or Binding, but that's obvious), so you can often get a 5 drop plus something else, which is where Terror of the Peaks is good. Against aggro, getting Gargaroth and Glasspool to copy it is big game. 

I think the 2 drops are the best for the deck. Ranger class is a great addition for getting creatures on board early. Omen of the Sea lets you find the Incarnations and work well with Lurrus and Setessan Champion. And Wolfwillow Haven lets you deal the curve being too high. There's some argument that the curve should come down and play stuff like dead weight or Warlock or Sorcerer Class and play some 2 drops like Scooze and Aphemia. That's fair, but I don't think it's necessary.