A screenshot documentation wont help you a lot if you are going to administer Unity. I suggest buying some books (Unity fundamental, Cisco Callamanager and Unity: step by step) these are really good books to start with, then use the Search function of cisco.com and look for Unity administration/Configuration..etc. Last but not Least the Cisco Netpro forum, if you have questions regarding Unity post them and you will get help :)
HTH
Karzazi