Not sure. Think I screwed it up with mine. It’s not very clear how to do it. You can’t change a username once you sign up, I know that, so you’ll have to make sure you use the one you want right at the start. There’s a way to change the name that’s displayed, but it’s difficult to tell what that actually does. I’m thinking to go back and delete, then rejoin to make sure I do it right but not sure I’ll be able to get that username, and also scared I won’t be able to sign up again. Lots of ppl here have done it, though, so there’s gotta be a way. I suspect it’s just a matter of carefully walking through the sign-up process and making sure you don’t miss where you can specify it. I don’t remember where that might have been but I missed it.