The Flueblocker is designed to be pushed into the narrow part of the chimney above the firebox. They are to be used only when the fire is out. The wool press-fits into the shape of the chimney flue, and holds itself in place with a pressure fit. Just push the wool pad into the narrow part of the flue, then tug it down gently to ensure a good fit.
When you want to light the fire, simply pull the Flueblocker down and put it in a bag. Each Flueblocker automatically comes with a 6” or 12” handle option. If the distance from the top of the fireplace to the chimney throat is more than 12”, then you may need to get a 6” extension rod.