You are the castle in the center, and you must conquer the castles with the English flag (white with a red cross). To do so simply press on the castle you want to attack. Then wait for your knights to return before attacking again. Make sure to press your castle when it asks if you want to upgrade. When all of the castles have the Scottish flag (Blue with a white "X") you have won.(It will be obvious if you have lost.) You'll get the hang of it. Good luck!