To back-up and sync your data between your devices, log into your gaiagps.com account from the app.
1. Go to the account tab.
2. Tap "Login" to set up your Gaia GPS account.
3. Tap "Make a Gaia Account" or "Log in with Facebook" to create your GaiaGPS.com account, or "I already have an account" to login with an existing account.
4. Turn on "Sync/Backup" to begin backing up your data.
Afterwards, you can find your data and manage your account by logging into http://www.gaiagps.com.