If you get that 5/6wt outfit from Amazon, I would go with a 7½ foot leader tapering to a 4X. Gander should have them. Might want to pick up a couple right away. Also pick up some tippet material rated at 4X and 5X. The tippet you will tie onto the end of the leader and change the tippet when it gets worn out or too short to tie on a new fly. That will save your leader from becoming too short.
Gander should also have a selection of flies. Get some of those woolybuggers (weighted) in black and olive size 8, Beadhead Prince Nymphs size 16, Beadhead Zebra Midges (black) size 18-20. I could suggest a whole list of flies for you, but those should catch fish for you here in AR. Also pick up some kind of stike indicator to help you notice the take of the fish. There are also fly shops here where you can purchase flies and get a better selection of what's working.
Tie your leader to your fly line, add a section of tippet about 18-24 inches long. To the end of the tippet, tie on a hunk of brightly colored yarn and then go out on your front lawn and practice casting. If ya got an old hula hoop laying around, place that on the lawn about 30 feet away and practice casting into that hoop. Your neighbors will think you flipped your mind casting out on your front lawn, but you need to practice in order to get to know what you are doing when you get out to fish.
There are a lot of videos on the net that show you the basics of casting. Study them and learn from them. It will be a big help in lew of taking casting lessons.