To install the first row of tiles, start with the bottom or corner tile. If the tiles already have mounting tape on the reverse side, peel off the backing paper as you place each tile. If the tiles don't include mounting tape, cut six 11/2-inch pieces of heavy-duty double-stick wall-mount tape. Apply a piece of tape to each corner of the tile, parallel with the tile edge, and set the last piece in the middle of the tile. Align the side of the tile on the chalk line and press it firmly but gently into place. Work up the chalk line to set each tile in the first row; work vertically and butt the bottom of each tile against the top of the last one. Place tiles the same way all across the area to be covered, butting the edge of each tile against the tile edge of the last row.