I don't have a video camera, and also would have no idea how to post it if I did. The way I start the mains is very simple.
1. Pull tension on both center mains, (This is just to set the 1st clamp is all)
2. Clamp the 1st string, 1RM,(1st Right Main), and also clamp 1RM at outside of racquet closest to machines tension head. This keeps some tension on that anchor clamp (the machines 1st clamp used), so it keeps the clamp straight and in line, and will not fall down.This string will be tensioned again later.
3. Pull tension on 1LM, clamp with machines clamp.
4. Pull tension on 2LM, clamp with machines clamp.
5. Go back and pull tension of 1RM, remove starting clamp, remove machines clamp that is on this string which is the anchor clamp, (since constant pull machine, this string will be properly tensioned exactly like the 1LM, no loss of tension).Then clamp this string as normal.
6. Continue stringing as normal.
This way, the 1st clamp (anchor), remains straight, and when you make the 1st pull against the anchor clamp, it puts the most stress against that 1st clamp, as there is no tension pulling against it like there is with the remainder of stringing the mains, so the starting clamp helps to back up that clamp, so you do not need to keep a too tight of a clamp on that anchor clamp, so it is easier on the string, and also will not need to worry about slippage.Many stringers can have that anchor clamp too tight, or too loose, and it can damage string, and shortly will see the string snap at the frame center main. Bring it back to the stringer, and he blames it on a shanked ball, (which can happen, but also can be because the 1st clamp either crushed the string, or was slipping and caused damage to string because it was not adjusted properly) ,This method is nice because the clamp does not need to be so tight, and holds well because it is backed up with the starting clamp. You could have also backed up the clamp with the starting clamp directly behind the anchor, but it will not keep the anchor all that straight doing it that way.