On the Zendesk dashboard, click the phone icon on the upper right of the screen.
On the drop-down menu, select Online.
The phone icon will turn green when you’re Online. This means that you’re now ready to take incoming calls. :)
If you need to take a break, just select the Offline option, so that no incoming calls will be routed to you.
ACW (After Call Work). Once you're done with the call, it will go to ACW status. Just click the Available to take new calls to accept new calls again.