Were do i edit foxycart templates an how do I get it started?
Design and Skin Customization
For the first question, I believe you would need a custom module, maybe one of the other guys can jump in and confirm this, I don't think there is a way to charge a different price for different types of audio, in fact I think the audio file that is purchased is the one that is uploaded. Jamroom takes the audio file uploaded and converts it into multiple playable files so it will play on PC's as well as mobile devices, if the file is for sale, Jamroom takes the original file and gives that to the customer after purchase.
For the second issue, I would make sure your FoxyCart account "Required Store Configuration" are all checked off. You should see this in your FoxyCart account dashboard.