Linux has made some serious headway over the past decade, elevating itself from “that open source operating system” to “wow, this thing is actually usable!” There’s been a gentle but definite trickle of users away from Windows toward the freer option of Linux and maybe you’re thinking about making that leap.
The fundamental structure of Linux is completely different from Windows–as it should be, considering that it was developed over a separate codebase with separate developers. You won’t find a My Documents on Ubuntu, nor will you find Program Files on Fedora. There are no C: or D:drives.
Instead, there is one single file tree and your drives are mounted into that tree. Similarly, your home directory and your desktop directory, they’re both part of that single file tree. Technically, you’ll need to learn a whole new filesystem and its architecture; practically, it’s not very hard, but the difference is still there.