Wall Removal

Where you removed the existing tiles you should have cut the back in a straight line down the edge of the tile using a utility knife or a key hole saw or better yet a grinder with a 4 inch diamond blade if you can handle the dust.  I usually try to cut the big back wall into four pieces and then the sides into two.  Be careful not to cut through the studs.  Take a hammer and bar then pry the pieces out.  Once you pull out a chunk or two out you will know how much you can pull out at a time.