Procedural Tilemap - need help

I want to create a map out of procedurally generated tilemap rooms. I have created a tilemap and an empty gameobject which generates the room with different tiles for walls and floors. But since it generates one room in this one tilemap, I cannot figure out how to generate multiple rooms and place them together in a map. Can I save a tilemap as a prefab? Or should I create as many tilemaps as there are rooms and have a script for each of them? I’m kinda confused. Not very experienced either.

Ok I created a tilemap prefab and instantiate it with each room generation.

Is there a way to detect if a tilemap is overlapping another tilemap? Collisions?