Google something + "Digital Ocean". e.g. "Deploy NodeJS DigitalOcean". You'll probably get a pretty good guide.
Negative Examples:
MongoDB - ...where do I even start? Literally. Where?
Mongoose - they eventually make sense, but only once you're already are familiar with how mongoose works...
Bootstrap v3 - This is contentious, but even after years of using Bootstrap, I always have difficulty finding stuff in the docs. I can never remember what's in the "CSS" vs "Components" vs "JavaScript" tabs and the navigation sidebar is painful to use
Positive Examples:
Negative Examples:
Edit: Bootstrap v4's documentation fixes most of the problems in v3's.