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.





http://www.youtube.com/watch?v=e5CGfoxnKaQ&feature=related
Here's a nice little video that always makes me laugh. You've got to love it, it's really so simple.... ;)
http://www.youtube.com/watch?v=yhajk_IDTUo&feature=related
There are literally dozens of videos on YouTube showing this process from the simple to the sublime.
http://www.youtube.com/watch?v=BVVE5EHzRnk&feature=related