take 4 cdx grade 4 x 8 feet of plywood. lay 2 sheets down and cross the other 2 down on top of the first 2. lay 1 piece of 4x8' of particle board in the middle of the 4 sheets. you can put liquid nails down or you can screw down all the sheets together. you now have 2 area's that are exposed....both are 2'x 8'.....you need to go to a feed store or rb rubber in oregon and get either a 4x8 sheet of rubber or 2 sheets of 2x8' of rubber. if you elect to get the 1 sheet of 4x8' you need to cut it in half....no easy task i might add. chalk a line on the rubber and get a tool knife and start cutting. pull up on the sheets as you cut...this will make it easier....it took me 15 minutes to cut thru a sheet. ordering from rb rubber is a more expensive proposition, but easier. drywall screw down all the pieces together including the rubber. if you go to the gallery section of the site, then to training facilities, you will see first hand the platforms at mikes gym being built. easy, functional way to build a platform!! enjoy!!