Don't worry. You'll be a pro in no time! I wouldn't ask that you start studying now just for this sake in case the roleplay doesn't start up, but if it does get more interest then I'd check out some helpful websites that explain it by typing in "riichi mahjong rules". I see a page on the Saki wiki that seems like it could be good but there are plenty of other sites as well. I'll explain anything that is still confusing, because it's indeed rather confusing at first glance.