Watch this video from This Old House to learn how to install a gas fireplace.
1 Prepare installation site by building wall recess to accept fireplace.
2 Cut hole through exterior house wall and install stovepipe thimble.
3 Attach short section of stovepipe to exhaust port on rear of fireplace.
4 Apply construction adhesive to wall around sides and top of fireplace opening.
5 Press granite slabs into the adhesive around the fireplace opening.
6 Slide the fireplace into position, making sure the stovepipe passes through the thimble to the outdoors.
7 Seal exterior of exhaust pipe with termination hood.
8 Hire a licensed plumber make the gas connection to the fireplace.
9 Install the removable front to the fireplace.
10 Turn on the fireplace and test its operation.