Make a series of reference marks for the top and bottom tiles image 1 that way you will know how many tiles to put on the wall.
How to tile unlevle bathroom walls.
The mortar is spread.
Lay your first row of tiles on the ledger board.
Using a long sraight piece of wood attach the wood to the wall using nails this is called a ledger board.
Set the wet saw table to 45 degrees to make miter cuts.
After finished height and the tiles are staying put remove the ledger board and install the missing row of tiles.
Back buttering is a trick used for tiles of uneven thickness like ungauged slate or handmade tiles extremely large tiles or for tiles being installed on an uneven surface.
I explain why this method works soooo easy.
Here is an easy way to set your 1st row and the rest going up your wall then lastly the first row is set.