To get to Jabber:
in the bottom left of your screen start typing jabber. You should see the Cisco Jabber App appear. 
When you click the App, you may be prompted to log in.
You will get a prompt for verification:
You should then see your initials with a green dot. (the green dot means you are connected and available)
To make a call the phone headset on the left side
Iin the Search, you should start to see options show up:
Chat
Group Chat
Phone Calls
Certificate
VIdeo Settings
Microphone See