While I have used a pizza box to demonstrate the technique, I've also had very good luck with 2 mm matte board from the art store. The matte board is stiffer and nicer looking than a pizza box.
I have not made any allowances for the power plug, but a simple hole in the crossbar will allow the plug to pass through. Feel free to modify the design to your own taste.
On to the first step!
Step 1: Print Out the Pattern
Try printing the larger one first and if it gets cut-off on the edges, then use the smaller one.
Step 2: Find a Pizza Box
Any stiff cardboard will do. Cut off a chunk big enough to make your stand. Like I said in the intro, I prefer using matte board from the art store. Whatever you choose, make sure it's big enough to be covered by the pattern.
Step 3: Attach the Pattern to the Cardboard
If you use staples, put them in roughly the same place I did so that they will be out of the way for the cutting and folding.
Step 4: Cut Out the Pieces
If you have one, use a paper cutter to cut along the main lines. After that, use some scissors to cut out the curvy parts on the main stand. I made several relief cuts to make it easier to get at the inside corners. Use your best judgement.
Since those inside corners are going to be covered by the crossbar, it's not super-important to get them perfect. If things aren't fitting later on, you can clean them up more as you need to.
For the crossbar, leave the small slits for later, those require some special fitting later on.
Step 5: Score and Fold Out the Legs
My preferred method is to use a pair of scissors to score the dashed line. Don't go all the way through the cardboard, just cut enough to help you bend it. Use the straight edge to guide your cut. Make sure it's super straight or your whole stand will come out wobbly.
After you've scored both dashed lines, bend the cardboard. The pattern will be on the outside of the fold. If you try to bend it the other way, that will not work very well.
Step 6: Make Slits in the Crossbar
You will need to cut out the inset slits so that the crossbar will fit over the main body legs. Make the width of the slits according to the thickness of the pizza box (or matte board) that you chose to use.
I used a scrap of cardboard leftover from the pattern to test against. Just gradually widen the slit until you get a nice snug fit. Be careful that you don't go to wide or things might get a bit wobbly and loose.
Step 7: Assemble Your Stand
Most likely if you're having trouble at this point, you've got to adjust the slits in the crossbar. You may have to make the slits wider or deeper so that the crossbar will slip snugly over the legs. If the inside corners on the legs aren't cut nicely, trim those out a little better and try again.
Step 8: Enjoy Your New Stand
I've also included some pictures of my version I made out of matte board. I like that one a little more.
If you use my design or make some modifications, send me a message, I'd really enjoy hearing from you!