Animal Crossing: New Horizons' second summer update has arrived, and it adds a handful of new features to the game, including a weekly summer fireworks festival, the ability to fall on your face, and save backups. You'll need to have a paid Nintendo Switch Online subscription to take advantage of the latter, and it works a little bit differently than the typical cloud saves offered through the service. If you're unsure how the process works, here's how to back up your Animal Crossing save data.
How To Back Up Your Save Data
After installing New Horizons' 1.4.0 update, you'll see Backups - Not Set beneath the Settings option in the lower lefthand corner of the title screen. Press the Minus button to access the Settings menu, then select Island Backup from the list of options that Tom Nook presents you to begin the backup process.
Once Island Backup has been selected, Nook will emphasize that this backup function is only intended to be used if your Nintendo Switch is lost or has been damaged. He'll then present you with options to Enable island backup or Listen to explanation. Select the former to enable save backups; select the latter to learn more about the process and its requirements.