Anybody can help me better understand how to use this trailer?

-orthopedic mattress (solved, change seats and activate in wheel options)
-TV (solved, use device options in the wheel options)
-Radio (solved, use device options in the wheel options)
-stove (solved, change seats and activate in wheel options)
-fridge (solved, change seats and activate in wheel options)

Need help with these:
-weapon rack - Which seat is this located and how much is the space?
-generator - how do we use the generator? I can turn it on but don't know what it's for.