Align the side panels with the edges of the front panel, clamp, and drill nail holes about 1" deep at the pencil marks using a 5/64 drill bit. (You must use this exact size drill bit so the nails will fit perfectly in the holes yet can be pulled out by hand). The nails will slip easily into their pilot holes and stand about 1/4" to 1/2" proud. Notice now nicely the front and side panels are aligned at the seam, but not the bottom panel which I will do later. Click on the picture to enlarge it to better see the nails in place.