I'll give you a step by step guide on how to do it and what materials you'll need, even some of the lessons learned from my ordeal.
Step 1: Go Shopping
First thing you need to do is go shopping. Here was my shopping list.
1. 6' Labrador Granite Right Miter Countertop - 59.00
2. 6' Labrador Granite Left Miter Countertop - 59.00
3. Miter bolt kit -5.95
4. Labrador Granite End Cap Kit - 11.48
5. 8' x 4'x 3/4" Pine Ply wood - 29.00 (worth it dont skimp on the ply wood)
6. Hole saw kit (need at least a 3" saw) - 2.99
7. Jigg saw blades - 4.99
8. Paint left over from painting my basement - 0.00
9. Gorilla Glue left over from remodel - 0.00
10. Metal Brackets handed down from dad when i moved out. - 0.00
11. Flat metal shim from the same dad - 0.00
Step 2: Gather Your Tools
1. Jigg saw
2. Circular saw
3. Power drill
4. Paint brushes
5. Saw horses
7. Common sense
8. Clothes Iron
Step 3: Make Your Leg Templates
Step 4: Cut Your Legs
I don't have a picture of this but you need to cut two, 2 inch wide by 22 inches long. This will be the top support for the leg. Then you will need to cut two, 2 inch wide by 24 3/4 inches long back support strips.
STOP. everything i said above with the top and back support strips needs to be rethought if you have base molding running along the floor. As you can see in the picture below, the spine support runs all the way down my leg, if you have molding, your leg will not sit flush against the wall. However high your molding is (mine was 4 inches) accommodate for it and shave off some of the bottom. For a reference you can look down a few steps where im screwing the legs to the wall you can see in that later picture that i trimmed off some of the back spine.
Step 5: Primer and Cut Your Holes
Cut your holes, I used a 3" whole saw but i should have used a smaller one. This will allow you to pass you wires through the legs.
Step 6: Paint
Step 7: Cut Counter to Size
I then cut the left miter countertop down one foot to 5' using a jig saw.
Step 8: Top Holes
Belkin carries two types of these, but i liked this one most because the hub was elevated and there was space to pass wires through the holes, which you'll need to pass up speaker wires, monitor cables etc.
Step 9: Join the Corners
Now, Run a large bead of Gorilla Glue (or equally as strong glue) down the mitered joint of the two countertops.
DO NOT OVER TIGHTEN, the under side of the countertop is just MDF and the joint is made of the same, if you over tighten you will break the joint. (mine started to crack).
Step 10: Line Er Up.
Step 11: Attach Your Legs
Then, find your studs and the best location for support for your legs. Then get to the screwing......
Step 12: Add Brackes for Support
Use the metal shims to join once and for all the two joints.
Step 13: Add End Caps
Step 14: Add Some Shevles
Step 15: Add Some Wire Rails
Step 16: Sit Back and Enjoy Your New Desk.
Enjoy. (i will)