Step 1: Arm Band
I found an old Futuro Sport arm band. You can use any arm band, just make sure it is wide so the GoPro doesn't tip over on your wrist.
Step 2: Add the Mount
I cut out the mount from the baseplate that comes with the GoPro, and hot glued it to the arm band.
Step 3: Your Done!
Just make sure the strap is tight on your wrist, and your ready to film some awesome stunts!