Okay, right now, you are using a player account by the name of BunniRabbi. You will use this player account to submit any characters that you want to play. After you have successfully gotten a ST to approve one or more of these character submissions, then you will be able to create another account using the exact same name of the character that has been approved to register another account. Your character account will automatically be linked to your player account, and will be then used to make In Character posts in the appropriate venue.
I am sure there's a much better write up around here somewhere on the wiki with pictures or something, but that's the gist of it; basically you don't have to worry about it until you have gotten a characters submission approved, and then as part of the approval process, the ST will send you the link to the instructions on how to create a character account.