The Free plan matches 24 people per round in unlimited matching channel(s). You can add the bot to as many channels as you want, not just the default matching channel called #coffee-matching made by on your workspace. However, all the channels will only have 1 schedule if you are on the free plan. (The Standard Plan offers different schedules to each matching channel and cross-matching channel group)

That’s to say intros are limited to 12 pairs(if you use the default group of 2 settings) per matching round. If you have more than 24 people in the channels, will randomly choose 24 to pair up each round, and will eventually cycle through everyone in the channel.