People Segments are used for campaigns sent to your own list of people. They are the group of filters that identifies the people you want to send Feelback emails to.
To configure the segmens of a campaign you need to go to the People Segment tab in the Campaign Console. The Following image shows where:
You can add your filters to redefine the people you want to send the campaign. Also a preview of your results are shown in Segment Results.
To send to all your contacts in your people module. Just add a simple rule like the one on the image bellow:
There are no limits for the amount of filters you may add, but remember to not duplicate the same filters to optimize your segment.