Go to the woodworking forum and check out the part about the sawboard. You will need a circular saw and a drill with a hole saw.
The circular saw will cut the angles you need with adjustment. YOu just need to figure out what angle you need it at. For somplicity's sake, let's say you want a 30 deg angle (too steep though, IMO). You will need to cut abunch of 120 degree angles (90 degrees is square, then add 30 degrees to get your pitch). To get the height of the legs, you would need the length of the front leg, the depth of the panel (the hypotnuse for the equation). YOu know one angle is 90 degrees, the other 30. That means the last one has to be 60 degrees (or whatever 90 minus your angle is). Use the formulas on this page:
http://www.themathpage.com/aTrig/solve-right-triangles.htmto figure the side I have markes as "A". then add that length to the length of the fron side and you have the total length of the back leg.
Sorry if that was too drawn out. If you can't follow that, PM me and I can help you out.
Go to home depot/Lowes and buy a sheet of MDF. That will give you wnough material to mess up a few times.
For the textured surface, I'm sure others can help you better than I can. I know people have mentioned it on here before.
Afer that, search around on here a bit more and you will find everything you need.