Friendly Battle is basically an arena battle with your friend. To start a Friendly Battle, you need to make sure your friend is on your ranking list. Tap on the “RANKINGS” icon and select the “FRIENDS” tab (leftmost). If your friend is not there, you need to add them first.
If your friend is on the list and available for battle, you’ll see a green dot next to their nickname and score. Tap on your friend’s name to open the “INFO” window. Next, tap the “FIGHT” button and wait for your friend to accept the challenge. Once the challenge is accepted, you can get your dinos ready for a fight!