It means that you are named Kouga, at that time you had only 1 post, and that no one had rated any of your posts yet, keeping you at the default rating of 3.00. Anyone with a 3.01 or higher karma can rate your posts based on merit. As you post, good posts will get rated up, and bad ones will theoretically get rated down.
registered ffxi characters means that you can make a profile that shows all the character attributes for your character, like what stuff you have, what skills, etc, so you can show other people.
Your character biography is where you can write things about your character, a "hello" message to people that view your profile, a story, a slogan, etc. whatever you want to write
Bookmarks, if you look at this thread, you will see an option in the left hand side of the screen to Bookmark (it has a little red flag) if you click on that, it will add this thread to your list of bookmarks, so you can find it easier later on.
Welcome to the forum!