Prepare the saw for masonry cuts. For a circular saw, install a masonry blade. You can use a cheap fiber-type blade for a few cuts, but a diamond blade is worth the expense if you have numerous cuts to make. Protect the base of the saw from scratches by covering it with a piece of 1/8-inch hardboard secured with tape. For a tub saw, set up the saw and table, and connect the water supply as directed by the rental company or saw manufacturer.
Mark the patio block for cutting by holding the unit in the position it will be installed and drawing the cutting line with a pencil or chalk.
Make the cut with a slow, steady motion of the saw (or saw table, as applicable). With a circular saw, start with a 1/4-inch-deep scoring cut, then repeat the cut a few times with the saw blade set deeper for each pass. With a masonry saw, you should be able to make the cut in a single pass. If the paver is too thick for a single cut, first cut halfway through the paver from the top side, then flip the paver over and complete the cut from the back side.