hey Jon Boy!! Welcome to the forum.
Let me get this straight.... you have a pawn shop and your getting into fly fishing....... either your in heaven or your profits are gonna go right down the drain (or both).
Those old Martin 61's are a pretty sought after reel. If you got that (and a rod) you might have made a very shrewd business deal, depending on the condition. I don't know too much about them, so hopefully someone else can chime in, but it should be more than servicable if you choose to use it. If you would rather keep it as a show peice and get a cheaper reel, go with a Pflueger Medalist. They got for about $25 and are built like tanks.
Since you have a 6/7 rod, get the 5/6 reel and have it loaded with backing, as well as a Weight Forward (WF) floating line. This is a general line and you can use it to fish both dry flies and stuff subsurface with a little bit of weight.
Since you have flies, all you will need is a leader. This connects the fly line to the fly. The size of the leader is dependent on the size of the fly. If you don't know the size of the flies you have, take em to a local fly shop and they will be able to give you the sizes, as well and help you choose a leader to work with them. But rule of thumb is the size of the fly, divided by 3, equals the size of the leader. So a size 12 fly will take a 4x leader.
The reel, rod, line, leader and flies are the bare essentials that you need to get out and start fishing. I've never fished for brim, but panfish are great to get started on, and are a lot of fun on the fly rod.
If you want any more info, this site has a search function in the navigation bar, called "Search" oddly enough
, and you can find tons of info here.
And if you can't find it, don't be afraid to ask.
Welcome again, and tight lines...