Jumping into an RP usually means asking OOCly if you can join, most likely making a character-sheet, and then making an intro-post in the IC which is basically a cold-opening zeroth-session that gets your character up to speed with the story and everyone else up to speed with your character; at least up to speed enough to begin interacting with you.
Making an intro, but being so far removed from the group their characters aren't even aware of your character until 5 pages later is less than ideal. I've seen it done, it can work, but it's more work.
Making an intro, but being so far removed from the group their characters aren't even aware of your character until 5 pages later is less than ideal. I've seen it done, it can work, but it's more work.