Hey NC!
It looks like this isn't yet supported natively, yet. You can vote for it here:
https://community.fitbit.com/t5/Product-Feedback/Stream-Premium-exercises-on-Fire-TV-Stick-device/id...
Though, you can try mirroring:
Use Screen Mirroring to see the entire screen of your Android device on the Fire TV Stick.
To enable Screen Mirroring on the Fire TV Stick, hold down the HOME button on your Fire TV Stick remote and select Mirroring. Alternatively, you can enable it in Settings > Display & Sounds > Display Mirroring.
Now, unlock your phone, head to Settings > Connections, and enable ‘Screen Mirroring.’ You can also find the option in the quick settings tile with different names like Wireless Display, Wireless Projection, Screen Cast, Smart View, or Miracast.
Once enabled, your Fire TV Stick name should appear in the list of available devices. Select the device and wait for the screen mirroring to begin. Note: Make sure that the Fire TV Stick, as well as your phone, is connected to the same wireless network.
