Virtaal is a graphical program for doing translation. It is meant to be easy to use and powerful at the same time. Although the initial focus is on software translation (localisation or l10n), we definitely intend it to be useful for several purposes.
The easiest way for most users to install Virtaal is through the provided packages, or through the packaging system of their distribution. On the Virtaal website there should be packages for Windows and several other systems. If you want to install from source code, you will need to ensure you have all the dependencies. For more information on building Virtaal to install it yourself, please consult the website here: http://docs.translatehouse.org/projects/virtaal/en/latest/building.html
Note that you will probably already want the Translate Toolkit installed and working before you attempt to install Virtaal.
Please report bugs by clicking on 'Help->Report bug...' from within Virtaal (this requires a Bugzilla account). Alternatively report directly using this URL: https://github.com/translate/virtaal/issues/new
Taking the time to create a bugzilla account will help ensure that you can track progress, provide feedback and allows others to see your bug report.