Thanks! A bit of both.
The first-match tutorial only teaches the turn loop — Vigor, play a card, pick a target, attack, pass. It reacts to what you actually do, so it never tells you what to play, just what's legal right now.
Deck strengths are spelled out before the match instead: the deck picker shows each deck's one-line strategy, a difficulty tag (Easy / Medium / Advanced, with what it rewards) and three representative cards. That's enough to pick on feel.
After that it's discovery, and the design helps: every deck is the whole faction, so its identity shows up on its own within a couple of turns — Rabbits go wide, Foxes hit early, Capybaras heal and hold the six slots. There's a Casual bot level for poking at a deck without being punished.