Where Your Stuff Is
If you open the icon for your main hard drive (Macintosh HD) from the Go→Computer window, for example, all you’ll find in the Macintosh HD window is a set of folders called Applications, Library, and Users.
Most of these folders aren’t very useful to you, the Mac’s human companion. They’re there for OS X’s own use (which is why Apple no longer puts the Macintosh HD icon on the desktop of new Macs, as it did for 25 years). Think of your main hard drive window as storage for the operating system itself, which you’ll access only for occasional administrative purposes.
In fact, the folders you really do care about boil down to these:
Applications Folder
Applications is Apple’s word for programs.
When it comes to managing your programs, the Applications folder (which you can open by choosing Go→Applications) is something like the Program Files folder in Windows—but without the worry. You should feel free to open this folder and double-click things. In fact, that’s exactly what you’re supposed to do. This is your complete list of programs. (What’s on your Dock is more like a Greatest Hits subset.)
Better yet, on the Mac, programs bear their real, plain-English names, like Microsoft Word, rather than abbreviations, like WINWORD.EXE. Most are self-contained in a single icon, too (rather than being composed of hundreds of little support files), which makes copying or deleting them extremely easy.
Home Folder
Your documents, files, and preferences, meanwhile, sit in an important ...