Introduction
Code packages that connects an Arduino board to different devices, including break out boards, sensors, displays, communication and storage devices, are available from different libraries. The Arduino app has a library manager that you reach from the menu:
The basics for handling libraries is explained on Ardiuons official page Installing Additional Arduino Libraries.
The Arduino hacking page on libraries summarises how to include both public and private libraries. The page includes a link to a test library and explains were to put your own libraries to have access to them when sketching.