Presence indicators give you details about a person’s status, including whether they are available, busy, or away. This short video explains how to use this information to make the most of your time and others’.
For more details, see the Help article Check a contact's availability.
Other videos to help you get familiar with Lync
Find even more videos in the Set up; Presence, IM, and Contacts, Make Audio and Video Calls; and Schedule, Join, and Conduct Lync Meetings trainings at Training courses for Lync 2013.