Cut a large piece of foam into a sheet 12 by 12 feet square. There are two types of foam you can use: Polyvinyl Chloride (PVC) or trocellen foam. PVC is recommended, and either foam type should be about 1 inch thick. You can cut the foam into multiple sheets that will form a square when put together.
Cut large sheets of 24-oz. vinyl into pieces that will cover all your foam pieces. Each vinyl piece should be the exact same size as the foam pieces. You need two sheets of vinyl for every sheet of foam because you're covering both sides of the foam. Line one full set of the vinyl pieces on the floor to simulate the mat surface.
Tape a wrestling circle onto the mat surface you laid out. The circle should be centered in the ring with a circumference of 10 feet using tape that is 1 inch wide. In the center of the circle, tape down starting lines that are parallel with one edge of the mat, 3 feet long and 10 inches apart. You will need to cut the circle/lines in places where the sheets separate.
Glue the bottom vinyl pieces (the ones without the circle and markings) to the bottom side of the foam pieces. You need a strong adhesive that will permanently affix the vinyl to the foam. Glue the top vinyl pieces to the top side of the foam.
Store rolls of adhesive tape that you can use to tape the mat pieces together when in use, thus preventing them from sliding apart from one another. You need tape that will firmly hold the pieces in place but can be removed easily after use. You may also want colored tape that is the same shade as the vinyl.