Clean the concrete surface, removing dirt and grime. If there are any areas with grease or oil stains, wash and scrub with a wire brush. Order the flagstones and crushed bluestones from your local home building supply store or stone yard.
Set the flagstones in place before applying the mortar. Create the design you want. Cut edges to fit with the wet saw.
Mix your mortar so you have enough to do five to six flagstones at a time. Trowel one inch of mortar on the cement. Wet down the flagstones with the clean water and sponge. This prevents the flagstone from absorbing too much water from the mortar.
Set each flagstone down on the mortar. Tap down with the rubber mallet. Clean up excess mortar from between the flagstones.
Place the crushed bluestone in the gaps between the flagstones. Choose pieces with a flat face for the top. Apply mortar to the cement and set in the bluestone.
Allow the mortar to dry for at least 24 hours. Place in sanded grout using a grout bag. Trowel it into the spaces between the flagstones. Sponge away the excess. Wait another 24 hours for the grout to set.