If you bought your licenses via some sort of Microsoft Volume Licensing agreement, then your keys should be available within the VLSC portal. Presumably, you got the ISO for Windows from there - just go to the Product Keys area and use those to activate your system.
The documentation you describe is for using the license and media that would have come with the system if you bought Windows with the server - so it isn't really applicable to the situation.
Edit: It seems like there's some serious confusion about how licensing works. I'd recommend you find someone who can help you with the basics. I'll also add that licensing is hard, so there's only so far we can help you here. But at bottom, you have to license at least two instances of Windows - the Hyper-V host, and each guest. Consider them to be separate devices - each must have a proper license, and its appropriate key.
(And I see someone mentioned Win7 earlier. You're not trying to activate Win7 with a Server license, are you? That won't work at all.)