For a tub surround only install the backerboard and tile 12 inches above the tub.
How to install ceramic wall tile around a bathtub.
Divide the dimension in half and make a mark there.
Check if you need to adjust this mark to avoid laying slivers of tile at the top and bottom.
When tiling around a tub mark the first layout line at the vertical edge of the tile next to the tub.
If the tub is level start with a full tile at its rim.
The best approach when installing cement board or other tile backer around a tub is to keep the cement board out of the lip area.
Diycrew hrvdiy renovision step by step tutorial how to install wall tile in any shower with any size bathroom tile including how to install tile in a nic.
Apply it to the wall with the bottom edge about 1 4 in.
I cover some of the specifics of how to layout and set up a tub to install tile around it.
Follow the order shown in the diagram to snap the rest of the lines.
Fill the gap between the tile and the tub with caulk.
Then apply a generous amount of thin set to the bottom bathtub tile and position it 1 8 in.