Okay, first, here's a list of software you absolutely need to have installed:
1. An SVN client (like TortoiseSVN
2. Microsoft Visual Studio 2010
. Either MSVC 2010 Express
or one of the more expensive variants if you have access to them
3. The Microsoft DirectX SDK
In order to get the actual code, you need to create a new folder somewhere on your HDD, right-click on it, and select the "SVN checkout" option from the context menu. In the dialogue that appears, enter the following URL:http://starshatter-open.googlecode.com/svn/trunk/
Leave everything else as-is, and click OK. The code will now be downloaded to your machine.
Another thing to do is to create a new environment variable called STARSHATTERPATH (all uppercase), holding the absolute path to your Starshatter install. This is used by the Starshatter solution to copy the created executable directly into the Starshatter folder.
Once it's done, open the "Starshatter.sln" file in the Starshatter directory. Once Visual Studio is done loading everything, You can press F7 to build your very own Starshatter executable.
Do note that, as of this moment, Starshatter is not cross-platform.