You have Gmod server running already, right? (You mention Windows dedicated, but we don't know if you mean Gmod windows ded)
Did you obtain the ULib addon? We currently recommand our newest (but not considered "release stable") code.
Did you obtain the ULX addon that runs on ULib? (again, newest)
Both latest code instances
ULib and ULX can be obtained through SVN, or by
downloading the ZIP from our github repository. The zip will contain other ulysses projects to, at first, you may not want to use them until you get ULib/ULX up and running.
Both have a readme file in the main folder describing where they need to be placed on your server, and how to add a primary user to get things started.
From there, it should lead to usage questions we can help with if not already covered in our
FAQ section.