Install the vertical roller tracks first by wrapping the curved lip around the rollers. The top of these tracks should be approximately 8 in. below the top of the top section. Wait to install the upper tracks until this step is complete. Check the level of the top section to make sure the tops of the vertical roller tracks are level with each other. The bottom of the roller tracks should be at least 1/8 in. off the concrete floor. After leveling and mounting these tracks, install the upper roller (horizontal) tracks.
The power to your garage is out with the door shut, and you need to get your car out or you'll have to take a bus. You'll notice a cord—usually with a red handle—dangling down from the guide track that the opener uses to open and close the door. This is the manual override. Once pulled, it allows you to open and close the door with your own power in the form a little elbow grease.