1. Lay side panel flat. Then insert top rail with cut outs facing in and up. Next, insert bottom rails with chamfer sloping down and outwards.
2. Place the second panel on the top once all locking bars are in place.
3. Slide the end boards into the grooves ensuring chamfered edge is towards top and slopes down and out. The top edge must be 7/16" below the top edge of the side panel.
4. Nail the side panels to the end boards using 16 x 50mm round head wire nails. (20 nails if making a 14 x 12 brood box). Nail the rails to the side panels as shown using 8 x 50mm round head wire nails. nail end boards using 8 x 40mm loose head nails.