That's a lot more work that what I made for my kids. I took a good sized piece of canvas, put handles on two opposite sides. Then between the handles I put a loop on one side and a big gaudy button on the other. Then I hemmed the cut edges. To use, lay it all on the floor and play. To pick up, fold each of the hemmed sides to the far handle side, then pick up by the handles and button. (more simply, fold it in thirds) Hang on hook, Legos off the floor so bare feet don't go ouch in the night.