To create holes for the adjustable shelves, clamp a piece of pegboard to the inside of each side panel housing the adjustable shelves. By drilling through the pegboard (which features holes predrilled 1" apart), at every other hole, the shelves will have perfectly spaced holes 2" apart.
Sand all the exposed surfaces with 220-grit sandpaper using a circular motion.
Begin the assembly by drilling countersunk pilot holes for each of the screws. Set the countersink so that the bit drills through the panel and the countersink bores a hole just deep enough for the head of the screw.
The holes should be drilled through each of the side panels 3/8" from each end of the panel and be spaced approximately 10" apart.