From your computer, go to the Fullscreen home page and click on your profile picture in the top right-hand corner. From there, click on Account and go to the parental controls section. Set the slide bar to “On.” You will then be asked to enter a four-digit passcode. Make sure you select one that only you know, and that isn’t easy to guess.
If you’re on your iOS or Android device, click on the “person” icon on the bottom right of your screen. You will then seen an icon that looks like a gear in the top right-hand corner. From there, go to Account Settings and then Parental Controls. Set the slide bar to on, and enter a four-digit passcode.