Only the biography field is required. Real name is optional. Your name can be changed via Special:Preferences.
What to put in the biography field: Anything you want, really; you just need to show that you're human and will have some use for your account here. Perhaps explain how you found LizardWiki, what you want to do here (some examples: Test out MediaWiki functionality, use LizardNet Code Review), that sort of thing.