Scrub the metal surface thoroughly with soap and warm water. Remove all dirt, oil and grease. Tile will not adhere securely if any of these substances are present. Either dry the walls yourself with a towel or allow them time to dry before you apply the adhesive. Again, if any moisture is left on the metal the tile will not stick correctly.
Apply an adhesive made especially for metal surfaces to the wall using a trowel. The specialty adhesive can be purchased at any hardware store. Place the tiles on the metal surface and use spacers so that you can create even grout lines. Allow the adhesive to dry for at least 24 hours.
Mix your grout in a 5 gallon bucket until it reaches the consistency of cookie dough or peanut butter. Spread the grout into the lines using a float. Remove excess grout from the tiles using warm water and a sponge. Allow the grout to set up for 72 hours and then apply a grout sealer to prevent stains.