Samsung Smart Switch for PC or Mac will allow you to complete a full backup of your S6 including storage or SD cards, (if applicable). Backups are saved to your computer.
There is also an app that installs on either an iPhone or Android device which is used for transferring content between two devices. The app is not needed if you're just backing up data from your phone to a computer
As for the loaner phone, visit a Koodo store with your phone and proof of purchase. If your phone is sent out for repairs, you have the option of using a loaner phone (if available) until you get yours back. A deposit is required for the loaner phone. If you can’t make it to a Koodo store, contact Koodo via Facebook or Twitter and request a Return Mailer, or request a Delayed Mailer if you live 25 km away from your nearest Koodo store.