Lay the polished stones on a surface, and arrange them in the pattern you wish to use. Wood and masonite make good surfaces for applying polished stones, because they can withstand the weight of the finished project.
Pour a 4 to 5 cups of powdered grout into a bucket and add water 1/2 cup at a time. Mix well. Continue until the grout is the consistency of a thick cake batter. If the grout becomes two thin, add more powdered grout and mix. Only mix as much grout as you can use in 20 or 30 minutes. The grout will begin to set up in the bucket if it is left mixed any longer than this.
Dip your putty knife or trowel in the grout, and smooth it over the stones. Make sure you apply enough grout and pressure to fill all the areas between the stones. Apply grout to the entire area.
Dampen a sponge, wringing out all excess water. Wipe the grout from the top of the stones with the sponge.
Allow the grout to harden for at least 48 hours before moving or handling. Keep the artwork horizontal during this time if possible.