OSP is the way to install the Chrome on computers OTHER THAN Chromebooks. Why would you want to install the OS you're running?
(BTW, you don't "upload" it "to" your Chromebook (that means that you're on another computer sending it to your Chromebook), you install it on your Chromebook. Bur as I said, you're already running it. It probably won't install over itself (which is a good thing - because you'd probably end up with a computer that wouldn't run).