You can click on the links below to navigate within this article easier. If you wish to run different versions of Windows in Virtual Machines, then the following D3K articles are worth taking a look at: But if you just want to try the Sierra MacOS, then the ideal solution is to use a Mac OS X virtual machine. In order to use it, you either need to buy a Mac or build a hackintosh.
MacOS Sierra is the latest version of Apple's operating system, which of course cannot be installed on just any computer.