These are two different things, decided by two different people, which is where most of the confusion comes from.
Rooms and roommates are yours. While the pairing window for your week is open, go to Housing, pick the week and gender, and drag campers from the Unassigned column into your church's rooms. Any roommate requests a family typed on the registration form show right on that camper's card, so you can honor them wherever the bed counts allow.
Small groups and staffers are determined by the Super Summer office. The Super Summer office builds the small groups, assigns a staffer to each one, and publicly releases them shortly before camp. Churches can't set them, and we aren't able to take requests for a specific staffer. Splitting a church's students across groups (schools/PrimeTimes) is very much on purpose; it's a big part of what the week is for.
Once assignments are released, Registration > Assignments lays out every camper's dorm, room, suite, small group, and staffer on one page, and the same information shows up in your Print Camp Packet PDF. Before release those columns read "Not assigned," which is normal behavior.