Measure the area in which the CSST pipe will be installed with a measuring tape. Cut the pipe the same length with a pipe cutter. Use light pressure when cutting to avoid burring.
Strip the insulation from one end of the pipe to expose the valley of the second corrugation with a utility knife.
Insert a nut onto the stripped end of the pipe. Insert a bushing onto the end of the pipe. Space the bushing so one valley of corrugation separates the bushing and end of the pipe.
Insert the pipe into the fitting on the gas furnace. The jacket locking feature will provide resistance as you insert the pipe.
Slide the nut over the bushing. Hold the fitting on the furnace in place with an adjustable wrench. Grab the nut on the CSST pipe with an adjustable wrench and turn it clockwise to secure into place. Rotate the nut only; do not rotate the fitting.
Wrap any exposed metal with teflon tape.