The only thing thats that you'll probably need besides what you get in your order, is cable and ends, and whatever you need to mount the dish to your home/pole/etc.
As far as adding things/pointing to more than one location, there are multiple satellites out there with programming on them for free. You'll need to take a look at what channels you want to view, and which satellites they are on. If you want to view channels from more than one satellite, you'll generally either get a motor to move the dish to view separate satellites, or add more lnb's to your dish. The GloryStar package is setup so that you can get their supported channels from two different satellites. You can buy a holder and two lnbfs so that you can get programming from both satellites without moving the dish. Of course, if you find that all of the programming that you'll want to view is on one satellite, then you don't really need to buy the extra holder/lnb/switch.
As far as hiring someone to do this, I'd be more inclined to just read...read...read and then ask questions until you feel comfortable enough to do this yourself. I have not heard of a single time that someone hired a person to come out and install a FTA system, and the installation was actually a success. Most of the installers out there are not familiar with true FTA, and they botch things up pretty well. There may be exceptions to this, but why bother when it's just as easy to do it yourself, if you're willing to read and learn.
And the question about having to "run a tuner often", I'm guessing they are referring to scanning to add channels. Until GloryStar has their channel mapping automatically working, new channels have to either be scanned in, or manually added. It's no big deal, and is not required in order to view the channels that were originally programmed into your receiver when you ordered it.