There are two distinctly different ways to link a section or bid to an externally stored cloud file.
You can either link a bid directly to a SharePoint site, which enables direct access and editing of any files stored in that SharePoint site OR you can link a section (or complete bid) to one of the many cloud storage solutions on the market – Dropbox, Google Drive, Box or One Drive.
See either of the two videos below explaining exactly how to do it.