The Public Display feature in RollCall Pro allows you to display a slightly different view of the action to the audience than what you see on your screen. In particular, the use of a Public Display window insulates the public from seeing your mouse movements, button selections, editing, etc.
To utilize this feature, you will need to extend your display onto a projector or screen rather than duplicate it. If you don't know how to do this, call your IT Department for help, but it's very easy to do.
Once you have extended your Desktop, then you can open a window for public consumption by using the "Open" option on the Public Display menu:
This will open a Public Display window over your screen. Click on the title bar of this window, drag it onto your extended screen, and then maximize it:
At various stages of the meeting, the Public Display will display agenda item wording, for example, as well as member's motions, seconds, and voting positions. You should become familiar with the differences between your display and the one the public sees, but you always have everything you need to run the meeting right in front of you.