Hold one of the dampers by the smaller end.

Examine the damper for notches or markings. Some dampers have a set of notches, or arrows, that indicate "Slow/fast". If your dampers have markers like this, use them to determine how far back you want to rotate your dampers.

Once you have determined how far back to rotate your damper, insert the large end of the damper back into the hinge assembly, leaving the small end sticking out. This will make it easier to rotate the small end of the damper.