This process varies slightly from JetBackup 4 and JetBackup 5. Some of our servers, at the time of writing this article, use JetBackup 4 while some use 5.
You can identify which version you have by the name of the option in your cPanel.
JetBackup 4 will show up as "JetBackup":
Restoring files and/or folders using JetBackup 4
JetBackup 5 will show up as "JetBackup 5":