Fire Sticks can't do AirPlay... I've got a Fire Stick 4K myself, and nope, AirPlay's a no-go. So, if you wanna mirror, you've got a couple of routes: there are mirror apps like Docast, Airbeam, or Replica. They're pretty decent, but they all come with a catch - you get a time limit on mirroring unless you fork over some cash for a subscription. And for Airbeam and Replica, you've gotta install them on both your phone and TV, which is a bit of a drag. Docast is kinda the easier pick here.
The other way to go is the old-school cable mirroring if your TV's got an HDMI input.