Recovery, in Android, refers to the bootable partition, in which the recovery console is installed.
It contains tools to help repair your installations as well as install official OS updates by using a combination of key presses or instructions from a command line sometimes.
Android is open, meaning the recovery source code is available, so that building a customized ROM is relatively easy.
1. For a start of this process you will have to turn off your device.
2. Wait few seconds and press and hold combined buttons: volume down + power button.
3. As soon as you will see the LG logo on your screen you can release the buttons.
4. Then after a moment of waiting you should reach Recovery mode screen. Good job!
5. Navigation here is really easy, just use volume buttons for going up or down and select with power button.