It looks like folks are really active on this right now....
Is there any way to see prioritize or get notice when someone responds to your thread or to your comment? (I might just not be looking hard enough in the app but it seems to just be chronological, which makes actual discussions difficult.
Normally, the idea is that as a developer, you rent a table for a certain amount of time and get as many people as you can/want to playtest during that time. There's not an official schedule to things. If you're not a developer who's trying to rent a table, there's no prereg, just show up. You start playing a game, finish it when it's finished, take the time to talk about feedback, and move onto the next game.