Installing VirtualBox on Windows

If you're not using a Linux flavor on your computer, and you're not using macOS, it's a good bet that you're running Windows (unless you've delved into FreeBSD on the desktop or similar, in which case I can't help you here—we'd need an entire afternoon).

If using Windows, I can suggest VirtualBox again, due to its cross-OS nature, and it can again be installed from Oracle's site.