TV Logging into subscriptions

If I already have a subscription for HBO / CBS and so on, how do I "log into" those subscriptions in the TV App. I see where you can sign up and it takes you to iTunes. However, if I already have a subscription to them, how do I enter it?

Replies

I have the same question and submitted a ticket for it. Without the ability, the TV app in Catalina is not of much use.