Once your concrete slab is ready, this project will take you through laying, leveling, and grouting the tile.
Spread thinset on the first layout grid on your slab up to, but not covering, the grid lines. Set the first tile on the grid lines and lower it into the mortar. Give it a slight twist. Continue laying the tiles and spacers, checking them as you go. If you need to straighten a tile that is out of reach, kneel on a 2-foot square of 3/4-inch plywood to distribute your weight. Cut at least two pieces of plywood so you can position one while kneeling on the other.
Periodically check to make sure the tile conforms to the layout lines in both directions. Lay a long metal straightedge or 4-foot level on the edge of the tile. This edge should align itself with the layout lines. Each joint within the pattern should be straight as well. Scrape off any excess thinset that may have spread over a layout line. Adjust the tiles to straighten the joints, if necessary.
When you have finished laying one section or grid of tile and checked all the tiles for correct alignment, set your level on the surface and look for tiles that are higher or lower than the rest. Make a beater block out of a 12- to 15-inch 2x4 covered with scrap carpet. If a tile is high, tap it into place using the beater block and rubber mallet. If a tile is low, lift it out, back-butter the tile with thinset, then reset it.
Let the mortar cure overnight. Then spread grout in one section at a time with a grout float, holding the float at an angle and forcing grout into the joints. Once you have grouted a section, hold the float almost perpendicular and scrape off the excess. Let the grout set and clean the surface as specified by the grout manufacturer.