How to activate Office Web Apps Server 2013

Hi!

I deployed a single-server Office web apps server farm like this article 

http://technet.microsoft.com/en-us/library/jj219455(v=office.15).aspx

I have licence for Office web apps server in my msdn subscription.

How can I activate it?

I did not find any article about activation. My Office web apps server don't ask me about activation during installation. I download distributive from msdn too.