You are expected to have an existing installation of Windows 7 or above. This allows you to choose the exact Windows version, patch level, architecture and virtualization environment yourself.
Once you have that available, you can quickly deploy the FLARE VM environment by visiting the following URL in Internet Explorer (other browsers are not going to work):
After you navigate to the above URL in the Internet Explorer, you will be presented with a Boxstarter WebLauncher dialog. Select Run to continue the installation as illustrated in Figure 1.