1. Remove the old door and the surrounding trim, molding, and door jamb.
2. Determine if the doorway is level.
3. Measure the doorway.
4. Purchase the necessary materials and tools.
Installing the Door
1. Pre-caulk the hard to reach areas inside the frame of the door.
2. Set the door in place.
3. Secure the door into the frame.
4. Install the sill pan and drip cap.
5. Caulk around the edges to make sure the seal it complete.