Content Caching Setup

Ok,

I'm trying to set up Content Caching on a spare Mac Mini and use it in our school network. From what I understand/researched, macOS Server is basically dead and I should instead just use the Content Caching feature to store updates for all of my Mac and iOS devices.

My question: Will my devices automatically find my caching device and download updates? I was reading about iOS devices needing to be tethered. Is this the only way to do it?