Each user should have their own profile so to allow the game to track their progress and match the correct skill level. Each account may have a total of 3 users per account. To add a profile the account owner will need to login on at https://game.keysandkingdoms.com/
Once you've logged in click profiles in the upper left corner
When you are on the profiles page you can select or add a child's profile from a dropdown menu and then users can choose from those profiles on your devices the next time a user starts the game.