The dashboard port can be connected to a computer either at competition or in testing, and it will provide the dashboard program (available at IFI FIRST I think) information on the status of your robot.
The dongle is an electrical device frequently used in testing. I'm pretty sure it plugs into the competition port on the board, and it allows you to set your robot in autonomous mode, driver controlled mode and disabled mode (I think that's it, I haven't used one in a while). If your team is interested in building one, there may be instructions in the whitepages section, or there is a simple wiring diagram
http://www.ifirobotics.com/docs/competition-port-pinout-guide-reva.pdf.
Hope this helps