When you hit the "Reply" button and the blank page comes up, look above the blank space where you write your answer, as I'm doing now.

The boxes beside "Your Name" and "Your E-mail Address" and "Subject" can all be written over. Just type in whatever you want in the "Your Name" box, like "John Doe # R-9547"

Also, you probably want to pick a Password and type it in the "Password" box just above the Preview & Post buttons at the bottom of the page. Answer "Yes" to Save Password, so that someone else can't impersonate you in later posts.

That should do it. Glad to have you here.