You do not need a pre-existing login to upload submissions. You can create a login at any time by going to the Login/Register link on the top right corner of the Public Portal.
From the Login or Register popup, click on the Create your free Bonfire account link:
All you need to do is provide a valid email address, a company name, and choose a password, and you're done! Your account is created and you can begin uploading your submissions.
If you have any questions please contact Support@GoBonfire.com