Issue with code!

Arduino: 1.6.10 (Mac OS X), Board: “Arduino/Genuino Uno”

/var/folders/3w/8qz2gv416gvg34cbvrzrf2bh0000gn/T/arduino_modified_sketch_965634/sketch_aug17a.ino:11:21: fatal error: NewPing.h: No such file or directory
#include <NewPing.h>
^
compilation terminated.
exit status 1
Error compiling for board Arduino/Genuino Uno.

This report would have more information with
“Show verbose output during compilation”
option enabled in File → Preferences.

this is the error message i always get.

(deleted)

How do I do that?