What follows below is the construction of a basic vacuum table for use in thermal vacuum forming of poly styrene. In the first photo you see the basic supplies used to create a simple vac box, or table. You need to plan ahead and decide what size box you need, make measurements and compensate for the thickness of your material. In the display below I used 2" X 6" studs left over from a construction project.
Photo 2 shows the basic box form. Always have a flat, level place to work and keep your form square.
Photo 3, measure and cut a piece of pegboard to your frame.
Photo 4, measure and cut plant stakes, or 1" X 2" framing in place to support the pegboard.
Photo 5, Use a hole saw to cut the appropriate sized hole for your vacuum hose and fitting. At this point you may want to epoxy a PVC fitting in place to get a good fit. Nail a piece of plywood, or MDF to the back (Not Shown) and make sure to caulk around every crack, or seam.
Easy peasy, you've made a simple vac table. See the links for video.
Here's a nice little video that always makes me laugh. You've got to love it, it's really so simple.... ;)
There are literally dozens of videos on YouTube showing this process from the simple to the sublime.