Please note that this option doesn't allow you to play on two devices! Thus, you will continue playing only on your new device.
You can transfer the progress from your old device to your new one as long as both operate on Android. To do this, you need:
  1. Check whether you have the Google Play Games app on both devices. If not, then install it.
  2. Connect the game to your Google account in-game Settings on your old device. Progress saves every few minutes.
  3. Wait until the time of the last sync appears (under the Connected button).
  4. Force quit the game, do not minimize it to the tray.
  5. Open the game on a new device and connect it again to your account.
Attention, always synchronize your game on the old device first and only then on the new one! Otherwise, the game session ends incorrectly, and you may lose your progress.
Please do not delete your account in the game settings on your old device! Instead, just delete the app from your device.