full documentation missing

I downloaded the arduino files from the website for a mac. Using a Zero. All I received was the app and no other documentation. I am looking for all library source code, wiring diagrams and how to connect the arduino pin names to the Atmel ports, etc. I have read these are normally provided but where are they? my drive has nothing but the app.

where are they?

Select the app, and do "show contents" from the menu, to reveal a whole hidden directory structure.

Did you install the Arduino SAMD Boards package? Go to Tools->Board->Board Manager. Click on "Arduino SAMD Boards" and then on the Install button that appears.