Well, everything's working on mine fine now. The site is http://store.fusco-moore.com if you want to check it out.
The thing you gotta look for is the "Attributes Controller". That will give you all the options for downloads. You have to tell it if you want radio buttons, a drop-down menu (like I have), etc.
You then have to set up download types. For instance, I set up my downloads to have the options of mp3 file, iTunes file, jpeg, and document. Then you make your products like you normally would. Then you have to go to the Attributes and select the product. Then you add attributes for the product. For instance, if my product is a song, I'll give it an attribute for an iTunes file and upload that iTunes file to the directory in the store so people can purchase it. Then, I'll make another attribute (and upload another file) because I'll have an mp3 version.
I'm sure all of that doesn't make much sense- it's a ton of steps. But, I found the answers here on the forum and now my store is running great!! Good luck,
~Jim