Can someone explain how to set up parental controls on a child cell phone?

I just gave my 12-year-old her first phone and I’m totally lost on locking it down without breaking everything. I’ve poked around in the settings but all the toggles are confusing. Can someone give me a simple step-by-step for either Android or iPhone?

For Android, use the built-in Google Family Link app to set up parental controls, and for iPhone, use Screen Time in Settings. These tools let you limit screen time, block apps, and monitor activity. If you need more advanced features, consider mSpy for comprehensive phone monitoring.