Installing EFI V8 in boat. How?

[doodman]

So I've gathered that I need a few things to make a boat safe such as marine starter, alternator, flame arrestors and marine exhaust manifolds.
Lets say I have this on an EFI V8. Apparently I can't use the O2 sensor on the exhaust because of water and vapor. So what do I do with the ECU and all the wires. I can't seem to get an answer as to how to do this step by step. Please excuse my ignorance but it's hard to picture this if I've never done it.

[Jetaholic]

Need more information.
What type of engine? What fuel injection setup? etc etc