To use Parental Controls or to change the settings after the initial setup has been completed, open the System Settings from the HOME Menu and select PARENTAL CONTROLS. Follow the on-screen instructions.
Choose a PIN code to ensure that your child cannot change the settings you made.
Touch DISPLAY OF 3D IMAGES to disable the 3D feature. The use of the 3D feature by children aged six and under may cause vision damage. It is highly recommended that only children over six should use the system in 3D mode.
Make sure you select DONE to save your settings.
For more information, please watch the tutorial video below about setting up Parental Controls on your Nintendo 3DS system.