In the bottom right hand corner of the YouTube Kids home screen you can access settings by clicking on the lock icon. Once you have demonstrated that you are an adult by completing a maths problem or entering a passcode you will be given the option to select ‘Timer’. You can choose a timer length from one minute to sixty minutes. This can be done by sliding the timer icon left or right or by using the - and + buttons. Once you have chosen your desired amount of time, click start timer.
When the time has lapsed the app will lock. Your child will receive a ‘Time’s up!’ screen. This screen can be disabled by clicking the lock icon in the bottom right hand corner again. You will be asked to enter the correct answer to a sum or to enter your own passcode, if you’ve set one. If your child is slightly older you should consider setting your own passcode as the sums aren't very difficult.