Connect apps to Apple TV App

I started the Apple TV app on my iPhone. It popped up and asked me to connect PlutoTV and one other app to the Apple TV app. It said that I could do this later if I wanted, so I skipped adding them. Now, I am ready to add them to the Apple TV app, but I cannot find any way to do this. What am I missing? I've looked in Pluto TV settings, in the TV app, and in Settings > TV, and I don't find any way to add apps.