You can build out a folder structure manually by adding folders individually. First, you'll want to make an index (also called a directory):
- In the Documents tab, right-click the top-level folder (usually called Document Sharing) on the left
- Select Add Index (or Add Directory)
- Name the index and click Enter
To add folders and sub-folders within the index:
- Right-click the folder you'd like to build out
- Select Add Folder
- Name the folder and click Enter