Find Arduino SketchBook

Hello folks,

I installed arduino in Lubuntu 16.04 LTS from "sudo apt-get install arduino", through terminal. I am folliwing this tutorial (https://www.arduino.cc/en/Tutorial/ArduinoToBreadboard) but I can't find the folder "Arduino Sketchbook"

How and Where I should go to find this directory?

It's set at File > Preferences > Sketchbook location/

pert: It's set at File > Preferences > Sketchbook location/

Thanks