Understanding Rails secrets/credentials

I personally have found Rails credentials really hard to understand. I think there are three reasons why this is.The official Rails docs about the credentials feature are a little terse and not easily discoverable.The feature changed somewhat drastically from Rails 4 to Rails 5, even changing names from “secrets” to “credentials”.I only need to use the feature once in a while, when I’m deploying an application for the first time, meaning there’s lots of time in between to forget everything I knew.