What Rick says to paraphrase "cleanliness is next to stickiness.
Alignment isn't difficult, I do the top first because it's a bit tighter. The bottom you can put a piece of waxed paper between the bellows & board 'til it's lined up & remove the paper when it's aligned. This works best if you double the paper over(one piece). The bottom will want to stick to the board, just a slow pull will bring it out.

The nice thing is no clamps are needed. Once the bellows is in place, close 'em a bit to clamp.