I want to install a short-throw projector onto the ceiling of a residential home and whiteboard onto a wall to hold the projected image. How do I do this myself or are there companies out there who can do it for cheap in the USA?
...you buy a projector mount, install it to the ceiling (normally requiring that you find the framing to get adequate hold) and provide it with power and signal cables (normally requiring a considerable amount of ripping drywall open to get those run - do yourself a BIG favor and run conduits, not wires, so you don't have to re-do the drywall work when things change.) Then you repair the drywall and paint.
It's not magic, it's just work. Either you do it, or you pay somebody else to do it, and aside from "companies out there who do it for cheap" being specifically off topic, there's also the little matter of getting your house burned down by some cheap fly-by-nighter cutting corners on the install. Always remember that "the US Electrical Code" is written by folks in the "fire prevention" business. Do you really want to bet your house on doing it wrong?
Alternatively, you live with exposed cables attached to the ceiling. It's much easier, and when you remove the projector it's just a few screw-holes to spackle & paint. I've done quite a few projectors for work, and most of them are exposed wiring.
Or, depending on the size of your proposed whiteboard, you discover that large TVs are remarkably affordable and brighter than most projectors, and skip the whole whiteboard & projector thing (done a lot of those at work, too, at half the price of the projector, and able to work in rooms much too bright for a projector to work in.)