I find the game plays best with 10 people, 2 of whom will be impostors. You can play with fewer, but unless I say otherwise, assume I am referring to a full game. I highly recommend getting a group of friends to play together, since public servers can be high variance in terms of who you end up playing with, and being in a Discord voice call while playing (though you can only talk during meetings).
Most groups of Magic players I know are playing at this point, so I’d reach out to your Magic friends (and point them to this article if they need convincing!).
You’re going to all want to be on Discord, and use push to talk to avoid talking when you shouldn’t. Someone makes a game, the rest of you join, and you’re in! One of the cool things about the game is that all the settings are tweak-able, so you can adjust your games very easily (some maps favor impostors, others crew, and you likely want to tweak settings if one side is winning too much).