What ever document vault you want to upload a file to the process is straightforward and similar in each case. 

Navigate to the Document Vault and click on Upload file. A pop up form will open containing different areas to be completed. 

To select the file to upload click on the add files button as highlighted below. From the pop up window you can drag and drop a file or click to open up the file directory from your device. 

With files being added to the staff document vault Visible to and Alert Users will not be available, however, for children and the school wide document vaults you should use these areas to control who can view the files uploaded and if you want anyone to be notified once the files are added.