airplay without wifi? how

You don't.

Being on the same wifi network is required.

Use AirPlay to stream video or mirror the screen of your iPhone, iPad, or iPod touch - Apple Support

Hello,

AirPlay only works without Wi-Fi under certain circumstances, if you are using AirPlay to stream video to an Apple TV you will need to be connected to the same network as your Apple TV.

Thanks for reaching out!

-Drake