Time for a visit to your favourite internet search engine, methinks.

I'm sure there are several sites out there with model control electronics - or check out some magazines.
BTW: the scale of your model makes very little difference to the electronics - so don't limit your searching to 'N' gauge!

For a novice, probably the best way to start is with a kit or a magazine project; you can see it working, get to understand it, and then start making some changes. You will soon amass enough experience to start your own project!