There are a couple of reasons you might want to connect your phone to your Firestick:
To cast or mirror your phone’s display to your Fire TV
To use your phone as a remote control
We’ve already discussed how to screen cast or display mirror above. Here’s how to use your phone as a Fire TV remote:
Connect your phone to the same wi-fi network as your Firestick.
Open the Fire TV app on your mobile device. (Download and install it if you haven’t already)
Select your phone.
Follow the on-screen prompt.
You can now control the selected Fire TV device from your smartphone!