Right ramp all day to light multiball and just keep going right ramp.
Each Multiball stacked on top of each other adds a ball and increases the Jackpot value shared between all the Multiballs.
Hold in the left flipper to send the ball around the orbit, then hit the right ramp on the fly for a skill shot.
During any regular multiball, you can bring in the others to progress towards Save New York. This is useful for harder ones like Sonar.