Ashok Khanna has a quick introduction to the basics of Dired. It’s not even a précis of the Dired section of the Emacs manual and doesn’t mention the essential Wdired mode but it is a useful post to get you started.
One interesting thing that I learned from it is that Dired is the original visual file manager. I always supposed that the idea was taken from existing programs and ported into Emacs but Khanna says it was the first and dates from 1974.
Dired, of course, is famously featureful and has many ways of operating on files and directories. As I’ve said before, even though I’m an old-timely command line guy, I mostly use Dired for my file operations. It’s just easier and faster and, of course, I don’t have to fire up a terminal app or leave Emacs to get the job done. I can even use Ctrl+x Ctrl+j to open a Dired session with the point positioned at the current file. If you’re an “everything in Emacs” person—or want to be—you really need to get comfortable using Dired. You’ll be surprised how much easier it makes your life.