It is really easy to affix a camera to any foam board these days! This video was quite literally our first wave.
I'm using these stab-through-the-board style GoPro mounts.
Choose a location on top of the board where you want the camera. It is likely far more interesting to have the camera facing you in its default, and most secure position. If you want other angles, You can use the myriad go-pro and tripod mount adaptors to work it out. Remember the mount is designed with foam cutting blades that'll hold it steady in the board while you rush down the faces of awesome waves. Pushing it into place will permanently scar the board, so removing the mount is a bad idea. Installing is a 1-time thing, so get it right.
You'll need a large diameter, Phillips head screwdriver, and a quarter. Again, installing one of these is a breeze if you give it a little bit of thought. Not thinking may result in ruining the board. If your board has a slick, laminated on kevlar/plastic type bottom and not exposed foam in a net style material, make sure to puncture the board THROUGH that layer (in the bottom and out the top,) because puncturing from the other direction will tear that layer loose. You MUST puncture a hole where you want to insert the mount to a) start the process and b) leave a clear channel for screwing the thing together.
Insert the top piece with some force, centering the piece over the starter hole. The mounting plate will cut into the board! Select the appropriate size screw-in bottom plate from the two that came with the mount, and use the one you think is right. Using the quarter, screw the two pieces together until they are putting a bit of pressure on the foam, and feel secure in place.
I suggest attaching the included string-tether to hold the camera to the mount in the event the screw-in bit fails. There is also a stabilizing plug seems impossible to affix once the camera is in place, and seems of dubious value. I have ignored it after failing to install it correctly.
We have HOURS and HOURS of video already.
No need to buy an expensive GoPro either, this $50 camera will work just fine.