Asklemmy

It likely depends on the courthouse, but generally speaking you'll show up, sign in, someone will give a little talk about how things work, and then you'll wait in a waiting room for a few hours while various names are called. Then you'll go into the court room and the actual jurors will get selected from the pool. They'll ask some questions and depending on the answer some people will get removed (having a family member who's a police officer is pretty common).

If you're not selected, you'll probably go back to the waiting room to see if you get pulled for another case. If you are, you'll sit and listen to the details of the case and eventually make a determination. Depending on the case/jurisdiction, you might also be a "backup juror" where you'll sit through the entirety of the case, but won't actually be part of the deliberation at the end unless another juror had to drop out for some reason.

I ended up getting a murder trial, which was pretty interesting. Overall wasn't a horrible experience, but definitely glad I brought a Steam Deck while I was waiting.