Cove base tile (Image 1) goes around the base of the room. It is a common tile used in your classic Art Deco style bathrooms. It makes the floor easy to clean.
You need to finish any painting before you install the cove base tile. It is recommended that you prime the walls first and then apply a semi-gloss finish in the bathroom to withstand the high humidity.
It is easier to "butter" the mastic on each tile (Image 2) rather than put it directly on the wall. Use the v-notched trowel to get good grooves in the mastic.
Wiggling the tiles into place on the wall will help create a suction to help hold the tile in place.
Note: You can butter a couple of tiles at one time, but don't get too far ahead of yourself.
If you get mastic on the tile, wipe with a dry cloth, or it can be scraped with a razor if it has dried.