Scott has pretty much covered it, but if you’re dying for something to read here’s a link to the wiki article for macros. Disclaimer: that article is almost a decade old. It’s probably still perfectly valid, but always take the wiki articles with a grain of salt since the maintenance of the wiki proved to be too much overhead for the project. There are a few other resources you can use to find information, but Scott’s google search method is going to get you most of what you’ll need.
I’ll throw in one “new guy” plugin suggestion: NppMenuSearch will help you find a menu item, plug in command, or setting. It’s no replacement for browsing around and seeing what’s available, but it sure helps when you can’t remember where the heck you saw the thing you’re looking for.
Good luck and welcome to NPP.