iOS Users:
If you are on an iOS device (iPhone or iPad), you can save your progress if you connect to Game Center. Game Center is an Apple service available for all iOS users and you can connect to it with an existing Apple ID. Once signed in, it should automatically link to your Dots & Co account upon opening the app to that Game Center account.
If you are on a device using iOS 10, Game Center is now accessible via the iOS Settings app. More details on how to connect to Game Center can be found here.
Android Users:
If you are on an Android device, you can save your progress by connecting to a Google Play Games Service account. If you do not have the Google Play Games app installed on your device, you will need to download it from here.
Upon having it installed, you should be prompted to sign into your Google account when opening Dots & Co and your Player ID will thereafter be associated with that Google account.
General Warnings:
Connecting to Facebook does NOT save your progress in Dots & Co (unlike Two Dots). Facebook is used solely to help you find your friends and send each other energy.
Signing in to multiple Game Center or Google accounts may reset your progress, so make sure to use a consistent account. Syncing progress across platforms is currently not supported.