So, the battle starts when you touch an enemy on the field. It then takes you to this screen and you go first. You have 10 seconds to: 1.Move around 2.Set attack 3.Restore health 4.Fire attack Once you attack or use an item or time runs out, it becomes the enemy's turn, so you have to dodge their attack.
Use arrow keys to move press z to change attack, and press space to attack.