Yeah, so HAI groups rooms into units of 8 or 16 (some panels are different, and I can't remember which it is off the top of my head). That's what the 1-1, 1-2, etc are. Room 1, Unit 1. When it goes to 2-1, that's Room 2, Unit 1.
You can have blank lines in the units setup, you don't have to start at the top and go line by line. So group your units into rooms... the first line of the room is the name of the room and also lets you select the technology, so be sure to choose RadioRA2. You will normally NOT put a real device in the first line of a room when you are using RA2. Then just fill in all of your devices, put in the integration ID, and profit.