We provide lots of very valuable documents for our software stacks. All these documents are included with the BeeKit installation. I strongly recommend you to check "BeeStack Documentation overview" (BSDOZB2007.pdf) which is located in the BeeStack 2007 folder inside the installation path for BeeKit. This document will tell you where to find valuable information in the other documents.
Also, I recommend you to use the application user's guide to check the step-by-step procedure to load the DEMO applications into the evaluation boards, and how to run the demonstrations.
Please notice that you "must" have the ZigBee specification document as well. You should contact the ZigBee alliance webpage to request this specification: www.zigbee.org
The MUST have documents are: ZigBee spec, ZigBee Cluster Library, and the Application Profile document (Home Automation, Smart Energy, etc).
Please use this community to ask any question you have in regards documentation.