Peel off the old carpet with your hands and pliers, if necessary. You may also have to cut out sections with the utility knife.
Vacuum all debris and loose dirt off the floor surface.
Run chalk lines diagonally from one corner to the other. The lines will cross in the middle, which will indicate the center of the room. Measure this distance from each of the four sides of the room, using a tape measure.
Wash the floor with a sponge, using a mild soap solution. It is also recommended to mop the floor so the entire surface is clean enough to lay the tiles.
Lay out all the tiles in the desired pattern to preview how they will look. This will assure that they fit properly, and that you will be satisfied with the design.