Welcome to our world..... New tools are a nice benny! Whatcha get?
Make sure the studs are plumb and on plane.(use a straight edge across the studs, make sure they all touch, if not fir them out) It will make the rest of the job easier. Don't have to be fancy with the cement board... A quick coat of JC above unit line to ceiling before you install helps blending into adjoining walls and ceiling.
