Site. Visit the Sites tab and see your site. Click it to go to the site's dashboard. On the left menu, click Products.
Product Type. At the top is an Audio tab and a Beats tab. Audio products are for personal use. Beat products are for commercial use in a another product. Click the one you want to add.
Create. Click the create button, fill out the fields and upload the files.
On the left, click Back to all products to see your product in your site's dashboard. If you enabled the product, you can see the product page for it by clicking on the link and pasting it in another tab. You can also see it on your site's home page.