I cant find it but I believe you first make your ticker in one of the online ticker websites. It will then give you a couple of codes. You want to copy the one that says message board codes. Come back to here. Go into the User CP area (top left side of the page). There is something that says edit signature. In there you paste the code you copied. Then save and I beleive it should work.
You can test that it works in this area.