How do i sign into paramount+ with SHOWTIME?

My account says i have Paramount+ with SHOWTIME, but ive never used it.. Triple Play Includes Preferred+, MAX, Paramount+ with SHOWTIME, HD DVR Service, HD Technology Fee, Gigabit X2 Internet, Xfinity Unlimited Select.

i want to watch the new star trek shows.. 

i have MAX and when i sign in, i just choose the xfinity option and it works.. 

there is no option for Paramount+ and it doesnt recognize my email.

when i try to put my comcast email in and sign up, it says i have to pay 12.99 a month. with no option to connect a service provider.

i just want to use what i already pay for.