How do I control the volume when connected to my tv?

When I first pair my AirPods to my TV/AppleTV I see a volume bar indicating where the volume is set on my AirPods but have no idea how to make an adjustment.

If I switch back to my phone, I can make them noise canceling or transparent and turn the volume all the way up. After doing that when I switch back to the TV the AirPod volume stays in noise canceling mode but the volume goes down to about half. I truly need a way to control my AirPods when watching TV.

Thanks,

Kelly