Hello Sid. I followed your link to sign.up.live.com and these snips show what I found:
I can't find any route to choosing between using my existing email and making it a Microsoft account or selecting the option that says "Get a new email address".
What should I do now please? Ideally I'd like to set up the account in a different name because when I looked at the above, it felt that my new and existing accounts would be linked, and I want the new account to be mainly using Firefox. I having massive problems with my outlook.com.