I recently replaced my hot water heater with a Suburban DSI 6-Gal water heater in my RV. How do I wire it up?

I’ve been looking online and can’t find an instruction guide on how to do this (or really any other information on it). It has 1 blue, 1 red, and 1 green wire which I need to hook up but am afraid to touch before I know what they are lol. Could end badly with a gas water heater (lol, j/k)

Thanks!