Hi,

I have recently bought an Arduino Due and I do not know exactly how to power it up; here http://arduino.cc/en/Guide/ArduinoDue is stated that I need to mount a usb cable to the port nearest to DC power supply meaning that this is responsible for power and programming. Is that true ? What is the other USB port for?

I am asking to prevent any damage to arduino

 

Frankly I'd suggest learning to read before you try to program a microcontroller..
Its all right there in the link you posted..

First sentence..

To connect the Arduino Due to your computer, you'll need a Micro-B USB cable. The USB cable will provide power and allow you to program the board.
Attach the USB micro side of the USB cable to the Due's Programming port (this is the port closer to the DC power connector).

Then just a bit further down the page.

The USB connector of the Native port is directly connected to the USB host pins of the SAM3X. Using the Native port enables you to use the Due as a client USB peripheral (acting as a mouse or a keyboard connected to the computer) or as a USB host device so that devices can be connected to the Due (like a mouse, keyboard, or an Android phone). This port can also be used as a virtual serial port using the "SerialUSB" object in the Arduino programming language.