Navigating in the Documents Tab is quite easy.
On the file tree, you have a few options available to you.
By default the last view you used, will be what you see when you next login.
All Documents - This shows all documents in this area
My Documents - This shows your owned documents
Company Documents - This will show a flat view of all files held in the drive with no folder structure.
Forms Snapshots - This functionality is part of workflows and will be covered elsewhere.
Archived Documents - This will show deleted documents.