Apply painter’s tape along the back edge of the countertop to protect the granite. Use a 3/16" V-notched trowel to spread white tile mastic (adhesive) on the wall. The manufacturer recommended this mastic for this type of tile. It's important to use white adhesive, because any color behind the tile will show through the glass. To apply, hold the trowel at 45-degree angle and use the notched edge to make ridges in the mastic.
Before pressing the tile into the mastic, go back over the whole area with the flat edge of the trowel to knock down the ridges (Image 1). This will prevent the ridges from showing through the glass. Even after they're knocked down, though, the ridges create air pockets that help adhere the tiles.
Set sheets of tiles into the mastic according to the layout (Image 2). Apply firm, even pressure to each tile to make sure it's set in the adhesive. If tiles fall off the sheet, simply press them into the adhesive; the beveled tile edge provides the spacing needed.
Cut tiles as needed with a wet saw. If leaving the tile job to take a break or cut tiles, make sure to scrape off any excess mastic from the wall so that it doesn't harden. Allow the adhesive to cure, then apply grout according to the manufacturer's instructions.