How to transfer files from an Android phone to a Ubuntu PC by using a USB cable? Im completely new user and inexpert. I made a video with the phone. How do l transfer it to an ubuntu pc? I plugged in the usb cable but apparenntly my pc does not see the phone. Thanks for help
First of all you don't need any USB cable.
You can transfer files from/to your android device with the Wi-Fi network of your device. Just install airdroid on your android device. Then activate wi-fi hotspot on your android and open the airdroid app. Next connect your pc to that hotspot, open any browser in your pc and enter the url provided by the airdroid app there. It will ask for your permission, click to connect. Done. 
   The good news is that this technique works in any Linux distro as well, I tested it on Ubuntu 14.04.1. It just uses your android wi-fi device and there is no issue related to mobile data plan i.e. you can use it without the mobile data.