A new steel or insulated door with a proper opener install is a two-person job at minimum, and it's not a good first DIY project - the door panels are heavy, the torsion spring under the header is under real load, and a slipped winding bar has put people in the hospital. If you're set on doing some of the work yourself, the honest split is: you can handle removing old trim, patching drywall around the header, or repainting the jamb before we show up. Leave the spring, the track alignment, and the opener wiring to us. We won't talk you out of tackling the parts that don't carry load, but we also won't pretend the spring tensioning is a weekend project with a socket set and a YouTube video.