One at a time, starting from the center, working outward, apply clear adhesive on the back of the tile and on the wood top (in a zigzag pattern) and place the tile on the wood. Wiggle each tile around to ensure it ise in the exact location you want. Then move onto the next tile, try not to bump the other out place but make sure they are pushed together at the seams (use a little clear adhesive there as well).
When the adhesive is dry, seal the top with shellac. Apply three coats. Make sure there aren't any gaps in the tile for the water to leak through.