Turn the lower bar on a c-clamp in a counterclockwise direction to open the clamp.
Slide the c-clamp onto the upper left portion of the track.
Twist the bar on the c-clamp to tighten the clamp on the track. Tighten the clamp as much as possible.
Apply a second c-clamp on the upper right side of the track, using the same installation method.
Test the security of the clamps by trying to raise the door. If they are properly installed, the door should be secure. If the door isn't secure, reposition or tighten the clamps.