Railrunnin, I use a small screw drive and tap it in first one end and then reverse and do the other end then tap it on the the shelf and connect the two together. they will mate right up and you will not even notice the seam. I had to use washers to shim the valleys behind the shelf otherwise they will warp on you. I spaced mine 5 3/4" apart. I cut 2 2x3's at 5 1/2" use used those for spacers. Start from the bottom and work your way up. If the bottom course is straight all of the others will be straight and even also.
Sometimes you will need to loosen a screw to prevent warping. That's OK. I have tons of this stuff and would not consider using any thing else.
