File Upload via File Picker
The file picker is one method for selecting and uploading files to your onCourse site, and is accessible via the Add an activity or resource link in your site (i.e. Add an activity or resource > file). More information about the file picker is available here.
Upload a file will allow you to browse your computer for a document.
Recent files lets you see the 50 most recent documents you've uploaded.
You'll only see legacy course files if you copied your course content from an older course in onCourse 1
Private files only appear to you but across all your courses. If you want to organize your files this is the place to start.