You will want to adjust the angle based on your personal preferences. You can do this by pulling up the excess cording, and tying a loop knot, that can easily be removed.
The metal pin is used to anchor your pillow into place. If you are working a project where the pillow needs to turn (such as a square or round edging) you will want to anchor the pillow in the center, with the pin straight. This will leave a small gap, which is fine. If there is any wobble, brace it with a folded piece of fabric between the pillow and the stand.
If you want the pillow to rest on the table, and be secured without being able to turn, then you will insert the pin in at an angle.