This is the JP1 beginners forum. There's no such thing as a stupid question in here, so post away, but this forum is just for JP1 users and people considering JP1, non-JP1 users please use the appropriate forum above!
It depends on the protocol selected. Some protocols include unit numbers. Most do not. Probably some with unit numbers don't make that obvious on KM's setup sheet (I'm not sure).
Some do have clear unit support. Try "GI 4DTV Official" for example.