Wiring question from a beginner

[Double Creek]

Complete rookie to boats here! I am rewiring a recently purchased boat. I have a yamaha single ignition swith installed and the wiring harness installed as well. Besides plugging the ignition into the wiring harness, what else do I need to wire the ignition to? There are several additional connectors and I'm lost.

Thanks in advance!

[99yam40]

gauges maybe, all depends what all is in the boat.

[Double Creek]

The only guages I have are a speedometer and tachometer, neither of which are wired yet. That's my next project.

I assumed I need to wire the ignition to the power bus?