Using an MB102 power supply with an Arduino Mega 2560

I'm sure this question has come up many times and I am very new to Arduino, but after searching the forum and the internet for about 43 hours I have yet to find an answer to this question. I'm sure it's operator error, not using correct search terms, lack of knowledge, etc. If someone would be nice enough to answer I would be very appreciative. This is my issue: I have a kit which contains an Arduino Mega 2560 and an MB102 power supply. The directions that came with the tutorial said to connect the MB102 because the Arduino power supply would not be enough to drive the required motors for the projects. But the tutorial gives no instructions on how to connect them together on the breadboard. The only thing I have found on the internet said I had to ground the MB102 to the Arduino power ground and to keep the positive wires away from one another. So does this mean that they are both powering the breadboard in conjunction with one another? Or is the MB102 powering the Arduino? Or is the Arduino being powered by its own power source and the MB102 is powering the breadboard? I hope this all makes sense and I have a feeling that all three questions have separate answers depending upon the application. I just don't want to fry my Arduino. Sorry for the long question and thanks in advance for any help given.

Power your Arduino the usual way, through the USB port, and then also attach the MB102 to your breadboard with a separate power supply to that. Either another USB power supply, battery or standard 240v PSU that provides 5V or 12V.

Then make sure you connect any power that your motors require through the breadboard PSU and not the Vout of the Arduino.

Hope that helps.