Quick Start Up Guide
http://learn.googleapps.com/products/quickstart/
Learn by Products
http://learn.googleapps.com/products/
Google Apps Tips Library
http://learn.googleapps.com/tips/#/list
How to use Google Apps at your Working Place
http://learn.googleapps.com/use-at-work/
Apps in action ; Ideas from you
http://learn.googleapps.com/use-at-work/apps-in-action/
What is New in Google Apps for Work
http://whatsnew.googleapps.com/
Help Center for Administrator
https://support.google.com/a/#topic=29157
Google Apps Certification for Administrators
https://support.google.com/a/#topic=29157
Google Apps Certification for Deployment Specialist
http://gfw-certification.appspot.com/deployment