It's important to remember that the Documents view is merely a view of documents that reside in the 4th Office. Documents added to the 4th Office from other places, such as the Feed (see this article) will also show in the Documents view. You can add documents to the 4th Office through the Documents view, and this article explains how.
Adding documents to the 'My Desk' Documents
Documents added to the 'My Desk' Documents view will only be visible to you once you share them with another User, Group, Project or Customer context. You can do this from the Documents by following the instructions in this article, or you can do it from the Feed by following the instructions in this article.
To add a document, click the + button and select to add a document from your local machine, Dropbox or Google Drive account. Any Google documents added via this method will be converted to a Microsoft Office document. If you wish to import and work with native Google docs please read this article.
You can upload more than one file at a time by multi-selecting the files from your computer. This is usually achieved by holding down the Shift key as you select the different files.
Alternatively you can drag and drop a file directly into the Feed from your computer, however we recommend using the method above if you wish to upload a large number of files at the same time.
Adding documents to a Group, Project or Customer Documents
If you navigate to the Documents of any Group, Project or Customer context, you can follow the instructions above to add a document. However, when you add the document it will instantly be associated with that context and visible to anyone else who has access to the context.
In the example below, Tom is adding a presentation to the Documents of the 'JJ LLP' Customer. This will mean the presentation is instantly visible to all members of the Customer.