Congratulations. My best advice - before you decide to install a McDonalds happy meal toy with an LED in the game that you *think* fits the theme well -- be advised that it does not look as good or cool as you think it will/does.
Otherwise, NVRAM is your friend and an easy upgrade to the game - never worry about batteries again.
The other advice - READ READ READ. After that the only way to learn is by doing. You will figure it out and we have a great community of people here to help. I'm amazed by the information on here. For example I was able to use playfield tear down photos over the weekend that someone else posted 4 years ago to identify what posts were incorrect/missing in my Funhouse. So much information here if you search or ask for it.