Wrap the band of the clamp around the glued strip or edge of the fabric on the furniture frame.
Slip the end of the band through a slot on the clamp mechanism -- this might be on the opposite side of the clamp from where the other end of the band is attached, or it could run parallel to the other end of the band -- and begin pulling the band through.
Adjust the fabric if needed before fully tightening the band.
Secure the band with the clamp mechanism. This could be an automatic ratchet, a lever you have to turn to tighten the clamp or a bolt you have to turn with a wrench. Older band clamps required a separate C-clamp to hold the two ends of the band in place.