Start by putting tile backer board tape on all the joints on the wall board and then put mortar over the backer board tape. Let the mortar dry and then you can begin the tile job. Install a ledger board at the base of the shower stall about one tile high. Draw some vertical and horizontal lines on the wall to help keep the tile going straight. Also use tile spacers to help keep the tile going straight. Mix up some thin set mortar. Put the thin set mortar on the wall. Apply it with the flat side of the trowel to get it on the wall then turn the trowel around and hold it at a 45 degree angle and use the notched side to run vertical notched lines up the wall. Do about 8-10 square feet at a time. Next start installing the tile using spacers to assure 1/8 inch spacing. Once all the tiles are set on the wall remove the ledger board and do the final row of tile at the base of the shower. Tape the bottom role of tile to the row directly above it. Next you will do the floor. You will apply thin set mortar on the floor of the shower using a 3/16x5/32 trowel with a notched edge on it. Before you put the tile down you have to make the mortar shower pan. The mortar shower pan is a flexible membrane liner sandwiched between two layers of mortar. Put a thin layer of thin set mortar on the shower pan. Lay the tile sheet down and press it into the mortar. Cut out a square opening around the shower drain area. Cut the sheet to the correct size to fit the last space on the floor. Cut some individual tiles using a tile nipper to fit around the drain. At the entrance on the outside put some 12 inch tile pieces down and on the landing of the shower. Let the tile set for 24 hours and then grout the tile applying it with a trowel sweeping across at a 45 degree angle. Let the grout set for 30 minutes and then wipe the tile wall down with a sponge. The grout should set up for 48 hours and then apply a grout sealer.