Just like most programming platforms, the Arduino environment can be extended through the use of libraries. Libraries provide extra functionality for use in sketches, e.g. working with hardware or manipulating data.
To use a library in a sketch, select itfrom Sketch > Include Library.
In our tutorial, all the library files needed for the program are included in the tutorial folder, we just need to add them to the IDE by following steps
Run Arduino IDE software and click Sketch > Include Library > Add .zip Library…
Go to the “addLibrary” folder, choose the zip library file, and click “Open”