Oh, sorry! The build should be pretty straightforward, then. You're basically building a box, right? So you need something to hold it up, and something to attach the soundproofing to. The cheapest thing to build something like this would probably be good old-fashioned wood. If you got some strapping (or maybe something a little more sturdy, depending on how large you want to go) and cut it to size, then build a basic cube around the area, using "feet" (more of the same material, parallel to where it sits on, like the floor or whatever) and then you can attach your foam to that.
If you want something that doesn't go all the way around you, then you're building something akin to a folding screen, so that it could stand on its own. It depends on how sturdy you need it to be, but the same thing basically applies. For something freestanding, you'd just need some plywood and hinges. If it's just a single wall, I'd probably use PVC pipe and fittings to put it together like a big Lego (well, a big round Lego) and then use an awl to poke small holes in your soundproofing and string them together with plastic zip ties and attach them to the PVC.
