From the customer feedback in the support request: 

I wanted to provide some feedback on the documentation. As a user I wanted to download an existing Continuous Backup snapshot.

Reading through the API documentation, it wasn't clear that "Create a Restore Job" was applicable.

"To learn how to download a snapshot", the documentation at https://docs.atlas.mongodb.com/backup/cloud-provider-snapshots/ directs the reader to https://docs.atlas.mongodb.com/restore-cluster/, yet that page does not include instructions for downloading a snapshot, only for Restore.