Roll before a session, so someone is ready when the players go where you did not plan, or roll at the table when they do. Keep what fits your game and roll the rest; Roll again leaves the kept rows alone, and Copy puts the whole character on your clipboard for your notes.
The tie is to one of the player characters: their brother, their business partner, a stranger to them. The secret is yours until the story gives it away. In ALRP an author can pass a secret to one player as a private note (Secrets), or hand a rolled character to a player to flesh out (Character Creation).