As you already know, in Windows just after the install there are a few standard directories like: Windows, Program Files, Documents and Settings/Users. In Linux a similar structure exists but with much more directories. I will present you below the most important ones:
/home = contains user’s personal folders and files
/root = contains the files and folders of root user
/dev = special files for system hardware devices
/etc = system configuration files for operating system and applications
/tmp...