I did the 99 cent/month bit through Amazon for Paramount+ just to watch the new Star Trek series. The unskipable promos and P+ logo (which *always* ran twice!!) before *every* episode was annoyance enough for me to cancel after the first month (and I paid for it with "slow shipping credits"...
I have no idea as I've not yet subscribed. I got those from one of the many articles about it and posted them for anyone who needed them and to have a place I could easily find them once I do subscribe.
I'd guess you enter them both during the initial sign up. There's little information...