The Winegard website has instructions on how to do what you want to do. They have also been posted here over and over. Docj is correct. It is not hard at all. You just need to put together three pieces. Your legacy (outdated) dish (antenna), a SWM-8 with power supply (PI29, 29v power inserter) and your HR-34 (receiver).
Rather than try putting an old engine into a new car, why don't you spend the money for a new Slimline dish with an SL3 or SL5 LNB (horn/eye) with a PI21 (21v inserter? RG6 (cable) to PI and then RG6 out to your HR34. That engine is made for your car.
Either mount the dish on a TV4RV.com HD combo kit or go to Camping World and have them install an SK-SWM on your roof. You can get a Slimline, LNB and PI on eBay for under $100.
You need to READ what has already been posted here.
Still overwhelmed? Keep an eye out for a DirecTV van. For a generous "tip" he/she will fix you up.
Another consideration is that every time you move you will have to re-aim the dish. Some find that daunting while others find in fun taking five to ten minutes.
The SK-SWM is totally automatic. Downside is $1500 or more with installation and if you park under trees it won't work. Ground-mounters have more flexibility in dish placement. I should add that there is also an older SK-3005 that is still required to get Locals in some markets. It also needs a SWM8 to be SWM compatible.
And then are the Locals and DNS. Again READ.