Build a Rectangular Frame
Out of the PVC pipe, cut four 3-foot pieces, two 2-foot pieces and two 1-foot pieces. The remaining pipe will be used later to make the handles.
Join one 3-foot piece of PVC pipe with one 2-foot piece using a T-joint. Then place another T-joint to the other end of the 2-foot piece, and then join another 3-foot piece to the end. Ensure the stems of the T-joints are facing upward. This will make one 8-foot pipe that has two T-joints that are sticking up. Repeat this process to make a second 8-foot pipe.
Glue a curve joint into each end of the pipes. Lay the pipes parallel to each other and insert and glue a 1-foot pipe into each curve joint connecting the two 8-foot pipes together. This will form a rectangular frame.
Build Handles and Frame Pads for the Rectangular Frame
Cut the PVC pipe into two 2-foot pieces and four 1-foot pieces.
Insert and glue a 1-foot pipe into each T-joint. Insert and glue a curve joint at the top each 1-foot pipe. Insert a 2-foot pipe into each of the curve joints to form a 2-foot handle. Repeat this to make a handle for the other side.
Take the two 1.5-foot square pieces of wood and cut the 2-inch foam to fit the wood. Take your vinyl material and cut it to completely cover the foam and wood and staple the vinyl to the bottom.
On each bottom corner of the wood, mount and screw a concave roller wheel with ½-inch wood screws using the electric drill. Once you have the four concave wheels mounted, set your roller pads between the frames with the wheels on top of the pipes of the frame.