How to reset Pixhawk 2?

#1

PX4 developer guide says:

Enable the uploader and then reset the board

How do I reset Pixhawk 2 (Cube) ?

#2

Basically I am following the developer guide right now and the only way I know how to reset the controller is to unplug and plug in the USB cable again. But the upload does not start. Had a similar problem with uploading Ardupilot firmware to the Pixhawk 2 through Mission Planner.