Microsoft has published an updated content related to Office Web Apps 2013.
This updated content convers Office Web Apps 2013 deployment and management, with a troubleshooting section which has been also improved.
http://technet.microsoft.com/en-us/library/dn135237.aspx
You also download a poster (available in Visio or PDF format) to understand how Office Web Apps 2013 is working as well as the difference with Office Web Apps 2010
http://www.microsoft.com/en-us/download/details.aspx?id=38833
Enjoy