LLuckham

I'm trying to add a ceramic tile tub surround and haven't been able to figure out how to add tile to the wall area only over the tub. Applying tile to the entire back wall is easy. It's the end walls that I can't figure out. There doesn't seem to be an object for a tub surround that can just be places and I've not been able to figure out how to limit the tiled area to only the tub, but not the entire end walls. How is this done? New User.