The easiest way to flash your Smartphone:
First install the android tools
sudo apt-get install android-tools-adb android-tools-fastboot
reboot your phone into recovery
For my nexus 4 it is holding down the powerbutton and the volume down key since the recovery appears.
plug the phone into your computer and sideload your android image
adb sideload cm-11-*.zip adb sideload gapps-*.zip