Getting HBO Max Free as Cox subscriber

Please  help.  HBO Max is free to Cox subscribers who have HBO, right?  That's me, along with all the other premium channels I pay for, plus internet.  HBO Max is even listed on my bill.  I hope I am not being charged for it, because a cost is not itemized next to where it shows HBO Max.  I hear that it is free if we have HBO.  Anyway, I'm trying to launch the app.  When I go to HBO Max on my Sony Bravia 4K TV, it asks "Already an HBO/HBO Max Subscriber? - click to launch app."   When I click launch app,  I then see ""If you get HBO through Cox Subscriber, , sign in through TV or mobile provider in Sign In Screen (below) and  then choose Cox as my provider and sign in with Primary Cox ID."  But when I click on Sign In, there is no Cox provider to choose and thus, no Cox sign in.  When I click on Sign In, it just provides a code  and  states to go HBO Max.com/sign in and type in the code.  I am stopping before doing that on my computer because I don't understand how to get to the place where I choose Cox Provider.and sign in with my Cox user name and password.  I know this must be simple and I'm complicating it.  I'm just confused.  Please help me through this process.  I have two Smart 4K TVs and a third oldie not so smart.