Many libraries and packages exist to aid with the SFTP connection, database restoration, and task automation. A few that we recommend are:

Additionally, for any manual file manipulation or transfer, FIleZilla is recommended. For more information about how to use FileZilla, please review the How do I access my FTP or Blackbaud Hosting Services Files Folder using FileZilla? 

Note:  Blackbaud will not provide support for the extraction of data from the .bak file using these methods