It does happen in Apa.. The waiting for your opponent but in all fairness it's not like there's a line up so you know when you shoot unless it was your captains turn to put up and he already told you he was putting you up
5 players play matches out of a maximum of 8 players on a team. One team posts a player for a match, then the other team posts one of theirs as a response. Next match, it's the other team that posts first and alternates each match. Strategies might have to change so there is typically not a starting roster for the night.