First things first, a list of the software required to do this. Most of the software is available for multiple platforms, but some software is platform-specific. You'll need access to a real operating system to run Admixture, by which I mean Windows won't work. It only works on MacOS, Linux, or other flavors of Unix. However, if you have plenty of RAM and a fast processor, you could run one of those operating systems in a virtual machine, using VMware or a free tool like VirtualBox.