Attach the side panels to the headboard using one 3-inch bolt through the top of the headboard into the top and bottom of the side panels. For added stability, insert one 2-inch bolt through each side of the headboard into the middle of the side panel end.
Assemble the crib spring assembly by inserting one 1/2-inch bolt into the appropriate holes along the bottom of the headboard and the front of the side panels. For a mattress which sits higher in the crib, use the top set of holes. For an older child, use the middle or lowest set of holes to situate the mattress low enough that your child cannot climb out of the crib.
Line up the holes on the front edge of the side panels to the holes on the back of the front panel. Insert one 3-inch bolt through each of the holes on the side panel into the front panel. Secure the bolts by turning the Allen key clockwise until the bolts are tightened.