Then, you can start to apply a thin-set mortar on to the wall. To prevent drops, put some papers on the counter. Then, you can tile the backsplash on to the wall. After all the tiles are installed, press them to the wall and after for about 12 hours, the mortar will be dry, then you can start applying the grout until all the voids between tiles are filled with grout. After that, clean the excess of the grout. The grout can stain. Therefore you need to seal it. After that, your backsplash is set. Furniture & Furnishing.