Lay out your design on graph paper, if you plan to use square tiles to make a specific design. This is unnecessary if you're using shards, as the shapes of the pieces will determine the layout as you go.
Spread a layer of glue or mixed epoxy adhesive to the back of each tile and place the tiles or shards, one at a time, on the lamp base. Use your graph paper design as a guide, if applicable. Leave 1/8 to 1/4 of an inch between tiles or shards.
Allow the lamp to dry over night once all of the tiles have been applied.
Mix the grout as directed. Apply it to the lamp base over the tile or shards using a putty knife so that the spaces between all of the pieces are evenly filled. Wipe the putty knife clean and use it to scrape the excess grout from the surfaces of the tiles or shards.
Allow the grout to dry for 10 to 15 minutes, then wipe the surface several times with a damp sponge to remove the excess grout on the tiles or shards until they're clean. Buff the tiles with a microfiber cloth to shine them.
Let the mosaic tiles and grout dry for about two days before using the lamp.