You can make sure that people know when you're reachable in Cisco Jabber by keeping your availability status current.
There are several ways that you can change your availability status:
Click the drop-down arrow next to your availability status on the main window and choose a status.
Hover over the Cisco Jabber icon on the taskbar and choose a status.
Right-click on the Cisco Jabber icon on the Windows system tray and choose a status.
You can also create custom status messages to expand on the default options.