How to download SmartSwitch

Unfortunately this method is not possible. In order for SmartSwitch to work with a phone, it must be downloaded/installed from the phone itself. If the phone is compatible with SmartSwtich, and the phone is in working condition, you can try (at your own risk) to download the APK file and side-load the app on your phone (download APK to your phone, open it with a File Manager like the My Files app, and install from unknown sources). Again, this is an 'at risk' option and make sure you trust the source of the APK to avoid infected/modified files.