Drill 3/8" holes in the end of your 2x4 pieces, 2" from the end and about 1" from the side (see below) This provides more stability on the end blocks once they are mounted.

Do It Yourself

Once the liquid nails have had a few hours to dry, line up one of your end blocks at the edge of the board (1" side closest to the middle) and drill holes all the way through the slideboard, using the holes in the 2x4 as a guide.

Cut your 2x4 into 2 foot lengths