The SDK files represent all of the 3rd party efforts which are, or once were, dependencies of the various opensource projects surrounding Sword of Moonlight.*

Basically what is included are the headers and libraries which are missing from the source code itself. You won't find the source code for building these libraries here.

Historically Visual Studio projects expect a SOM_SDK environment variable to be defined. It should point to the SDK folder wherever it is installed on your station/network. Unzip the various SDK files to that folder. If Visual Studio is open as you are defining SOM_SDK it will have to be closed down and fired back up.

*Hosted under http://svn.swordofmoonlight.net/code/.