A predictive dialer calls a list of people automatically. When a call is answered by a live human, it immediately connects the call to an agent; if a call is answered by an answering machine or voicemail, it either hangs up or leaves a message.
Agent Dashboard is a software phone on your computer. You use a computer headset to talk to your customers. This software can be downloaded from the Setup, Download main menu.
If you have problem setup the software, please see How to Setup Agent Dashboard for more info.