How to power motors and Rpi using Explorer HAT Pro

Hi there

I’m a beginner in electronics and Rpi. I’d like to build a simple robotic car to start with.
I’m considering buying a Pro HAT board.
I saw similar posts in this forum, however one thing isn’t clear to me.

Is it as simple as connecting the motors to the Ex HAT Pro and connect the power to the main power micro USB of the Rpi or should I have a separate power sources for motors and Rpi.

I read elsewhere tutorials about Rpi and motors (http://business.tutsplus.com/tutorials/controlling-dc-motors-using-python-with-a-raspberry-pi--cms-20051) and it was recommended to separate the power sources.

thx in advance
Alberto