Remove the two twin bed mattresses and box springs from the metal bed frames and set aside. Lean the king headboard against the wall in the area where you’ll place the bed.
Attach the swing hinge headboard brackets to the left and right sides of your king headboard. Line up the holes with the holes on the headboard, positioned so the two pin holes are on the outer edge of the headboard sides. Bolt it into place using the hardware that came with your headboard.
Attach the swing hinge bed frame brackets to the two twin bed frames. Attach one swing hinge bed frame bracket to left side of a twin bed frame and one to the right side of the other twin bed frame. Line the holes up on the brackets with the holes on the bed frame and bolt into place.
Connect the left twin bed frame to the left side of the king headboard by sliding the bed frame bracket into the headboard bracket. Slip the pins that came with the brackets into place where the holes line up, which secures it to the frame. Repeat on the right side and replace the mattresses to finish the connecting process.