Hey NanaTech55, easy peasy. Samsung Kids is a great built-in tool for this.
- Swipe down from the top of the screen to open the Quick Panel.
- Tap the Kids icon (it looks like a little kite). The first time, it’ll walk you through setting a PIN.
- Once inside Samsung Kids, tap the three-dot menu and select Parental controls.
- Enter your PIN. Here you can add allowed apps. Just add PBS Kids and the games you want. They won’t be able to exit or access anything else without your PIN.
Pro tip: In the same menu, set daily playtime limits to avoid arguments when screen time is over!
For more powerful, remote control over their devices when they’re not with you, I use Parentaler. It lets me block apps and websites from my own phone.