If you believe in your use of the word handy there is no reason you could not do it yourself. You are only talking about measuring and cutting plastic pipe and mounting the tank or tanks. Odds are you will do a better job.
I would suggest you install both a gray and black tank if you intend to use the trailer beyond campgrounds with sewer.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles