The training for Cisco Jabber can be found on the Cisco Webex Help Center for Jabber. Below are a couple of links and videos we believe will be helpful in getting an overview of how to use the Cisco Jabber for Windows. Videos may include features unavailable in our specific Cisco Jabber deployment.
Getting around the Cisco Jabber App (Video)
Calling Basics (Video)
Add Custom Contacts in Jabber