You can add existing content from outside the
application and create new content within the site in order to populate the
document library.
The Upload action enables you to upload existing content from your computer into the library.
The Create Content menu provides options for creating plain text, HTML, and XML documents directly in the library.
It also enables you to create three different types of Google Docs content items: documents, spreadsheets, and presentations.
For both methods, it is important to understand how to create a folder structure within the library to organize the new content items.