usually there is screws that need to be tightened. however they also may have stripped out. Get some wood glue and sawdust and mix them. fill the holes and poke it a bit with a tooth pick to get the air bubbles out. let this dry for 24hrs. using only a hand screwdriver not a drill rescrew them in. If you find a support that is cracked when you take it apart fill the crack with the wood glue and find a way to clamp them together. same let sit for 24hrs to cure and reassemble.