The great thing about these is they're light, cheap and the thumb tacks only leave little holes so if you rent like I do, you don't have to worry too much about filling in the holes when you move out!
Cut the fabric about an inch beyond what is required to fit the corkboard and lay the board in the centre of the wrong side of the fabric.
Wrap the fabric around the board and with your fancy schmancy stapler, staple it down. Don't worry about the corners yet.
Tuck the fabric in as shown and staple it down a few times for good measure.
You should now have a board covered in fabric - good job!
Flip the board onto it's front so the back is exposed to you and plug in your hot glue gun.
Glue down the tacks where ever you feel the need. The corners are a good place to start.
You now have art or a pretty place to pin phone numbers!