Good luck with that, the highschool I went to had a hard enough time getting students to stop vaping at school and during class, smartphones would be a much bigger battle. I graduated in 2019 and I still remember when they would try to crack down on cell phone use, never really affected me that much cause I only ever used my phone during class if I was done with everything but I still saw it go the same way every time. It would always only ever last for a month or two before the teachers just gave up because in the end if someone doesn't wanna pay attention during class taking away their distraction isn't gonna make them. They'll just find some other distraction like talking to people or just zoning out. The problem is school just isn't engaging and sure you can blame cell phones and social media for making it harder for people to pay attention to things that they don't wanna do. But that doesn't mean the solution is to not allow them during school, cause I've seen from experience that doesn't help even if you manage to take away the phones, which already is really hard without impacting students who are following the rules negatively.