To be able to connect your game to Facebook:
1) Make sure you have logged into your Facebook account on your device
2) You must allow the game to access your Facebook account. Open the device settings, tap Facebook and make sure you have logged into your Facebook account. Also, check that Empires & Puzzles is enabled under "Allow these apps to use your account"
Please note that the only way to save, recover and sync your progress is by signing in to Game Center (on iOS) or Google Play (on Android). When you start playing with your new device, your old account will be automatically restored as long as you're signed in.