Within downloads there are various other global settings that can be applied to your downloads area, and also setting regarding paid files which you can set.
Paid files will be unavailable if you do not have the commerce application installed, as there is a tight integration between the two applications.
All sections below are found within the following area of your admin CP
Community -> Downloads -> Settings
On the first tab, you can set up which items you wish to be able to see on the index page of your downloads section. By default, all items are switched on, and selected to show from all categories. This can be changed to show only certain categories and sections, as per your own preference.
Index Page Settings
Within the basic settings From here you can set up whether or not watermarks are applied to any uploaded screenshots, and other global settings such as allowing direct linking to files on other sites.
If you have the commerce application installed, you can also allow paid files to be added to the downloads are by your users. You can find these settings within Community>Downloads>Settings>Paid Files Settings.
You will notice within here, you can set commission for the site to earn on whatever is sold by the user within your downloads area. This can be a good source of revenue for your site.