Some of this you can do. Weatherstripping, tightening loose hardware, lubricating rollers - fine, have at it. Installing the door itself is a different job. A double garage door panel is heavy enough to do real damage if it drops while you're setting it, and getting torsion spring tension right on a new install is not a place to learn by trial and error - wound wrong, that spring can put you in the hospital. If your opening is a nonstandard size, which is common enough in the older stock around Costa Mesa, you also need someone who can size a frame kit correctly the first time, because an ill-fitting jamb extension shows up as a door that binds within a month. We'll say plainly: this is the one we don't recommend as a homeowner project, and we won't sell you a kit and walk away.