After getting a new board and bindings ive realised ive never really never set up a board. My existing board is a Airush switch 142, the new one, a Core fusion 5 and union pro bindings. The old board was set up on the second screw left and right, but ive read if you're under 6ft you should use the two inner screws L and right.
Im 178cm.
Also a few images attached to show what I mean

I noticed the distanve between the first screws vary on boards.. i set up on the inner screws.
Attached is the board image.

Put a tape on the ground and stand in the stance you would for .. playing pool / tennis / boxing / skiing , you get the idea. Check the distance between you feet and set your pads to that :)

Try them all. Some boards feel better with a narrow stance, some with wide. Pay attention to how it feels on your knees too...