No, you don't need two different accounts, but when you register you can only select the 'Coach' account.
Once your account has been confirmed, the 'Champion' status can be added to your profile by the Administration team.
Once logged in, if you have more than one account, there will be a person icon in the top right hand corner of the screen, click on the person icon and it will tell you which role you are currently logged in as at the top and below it will say 'Switch to ...' the other role.
Click on the other role and you will be then logged in as that role.
Repeat the process to switch it back.
Please note: Champions and Administrators can't register - they have to be added by the Administration team.