HBO MAX Sign In

Hello, Currrently receive HBO channels on TV so assume I receive HBO MAX with subscription. With this said I downloaded the HBO MAX App on my phone with my comcast User name and password and works but I want  to be able  to use the  HBO MAX App on my Sony TV. So everytime I do this it shows a code on my tv  screen and say's to HBO MAX.com or App and add code but can't see where to add the code. Can you use the TV App of HBO MAX with Xfinity Subscription or just App on Phone? Not using X1 box, using Cable Card.