Hi @transcript-junky, you can find the calendar of all tournaments here. If you click on the event, you'll see related links to the Challonge site (you need an account to sign up for the tournament, and also sign in within 30 minutes before the game) and the Discord channel where the organizers assign who challenges whom in the tourney-players channel.

The tournament uses EST so be sure to convert using the link provided at the end of the Tournament description on the Challonge site.

Hope that helps, and thanks for stopping by!