The first step is to make sure that the wall is actually straight against the door frame and floor.

If your baseboards aren't level, move the bottom row of mirror tiles up a couple of inches to where you won't notice the uneven baseboards, and begin your mirror wall there.

The next step is to add the double-sided adhesive and place one in each corner of the back of the mirror.

One tile at a time, peel the backings of the mounting squares and press the mirror tile onto the wall.

Working from the bottom up, add the mirror tiles, one row at a time.