diy

I've been preparing to replace the tub in my guest bathroom, the tub has been out of level since I bought this house, and it has always retained some water in the back, which had also always been somewhat discolored. For context, the walls had previously had tile up to the ceiling. I've been trying to read and watch as much prep material in advance as I could, but in all of the material there had always been 2x4's behind the tile and some sort of backer board. As I'm pulling down these tiles, what I find instead is brick wall. In summary, I haven't been able to find any resources describing prepping brick walls for a new tub and tile. I don't know how I ought to attach the tub to the walls (if that's even something I ought to do in this case) or how to otherwise prep the wall to receive waterproofing and tile. Any materials or advice offered would be greatly appreciated!