Disconnect the stove pipe if there is a wood stove connected to the chimney. If it is a fireplace, open the damper.
Clear the inside surface of the chimney of ash and creosote using a chimney brush on a flexible pole.
Unroll the flexible steel chimney flue on the roof in preparation for feeding it into the chimney. Measure the distance from the top of the chimney to the pipe collar or damper at the bottom. Trim the liner to a measurement 1 foot longer than this distance using tin snips, to be sure that you have enough length.
Feed a rope down the chimney to your assistant at the bottom. The assistant will access the rope through the collar hole for the stove pipe or through the damper of the fireplace.
Gently feed the liner down into the chimney while the person at the bottom pulls it down with the rope. Avoid flexing the liner any more than necessary.
Attach the top of the liner to the top of the chimney once it is completely installed inside the chimney. Put a line of waterproof silicone around the lip of the chimney opening, press the top edge of the liner into the silicone and then apply the supplied cap over the top of both the liner and the chimney. Secure the cap with tapcon screws driven into the masonry of the chimney.
Attach the bottom of the liner to the collar of the stovepipe opening or to the outside of the damper using heatproof refractory cement.