Pour the dry mix into the bucket first and then add sufficient water based upon the instructions included on the manufacturer’s container -- different types and sizes of bags require different amounts of water. Use a margin trowel to blend the dry mix together with the water and let it sit for 10 minutes to activate the chemicals in the grout. Mix it one more time.
Spread the grout over the joints you want to fill. Hold the grout float at a roughly 45-degree angle while you apply pressure to the float handle and force the grout into the joints between the tiles. Pull the grout across the joints from multiple angles to ensure they are sufficiently full, and remove the excess grout for cleaning.
Wait 20 minutes before cleaning the surface of the tile. Fill a bucket with water and dampen the tile sponge; do not let it get any wetter than just damp. Lightly move the sponge in circular motions across the joints to remove excess grout and smooth the joints over. Rinse the sponge out frequently. Rough-wash the floor and change out your water.
Wait another 30 minutes before final washing of the floor. Dampen the sponge and pull it diagonally across the face of the tile and the joints. Apply only enough pressure to remove the final film of grout off the face of the tile, as too much pressure will dig out the joints. Rinse your sponge out frequently and let the installation dry for at least 72 hours before allowing foot traffic.