Don your safety apparel -- gloves and safety goggles are required. A thick jacket and a faceplate are also recommended to protect you from granite shards and splinters.
Place the granite slab on the saw horses or on the table saw so the polished side is facing up. You always want the polished side of granite facing up, as this will lessen the chance of a chip or crack in the polish while cutting.
Measure out your cut with a tape measure or straightedge. Draw a line along the tape measure or straightedge with your marker. You will follow this line with your power saw or table saw when you are cutting.
Position the blade of your saw so that it is almost touching the granite. Line up the blade with your marked line.
Turn on the saw and guide the blade slowly into the granite. Do not try to force the blade through the granite, as this could damage your saw.
Spray a light amount of water into the cutting area with your spray bottle every few seconds. This will help keep the saw blade from overheating.
Continue until you have finished your cut. Repeat Steps 2 to 6 as needed until you have successfully cut your granite slab into the desired shape.