error compiling with the ws2812 RGB

error compiling with the ws2812 RGB WHAT SHOULD I DO TO SOLVE THIS ERROR??? Arduino: 1.8.1 (Windows 7), Board: "Arduino/Genuino Uno"

E:\projects\RGB_ws2812\RGB_ws2812.ino:5:32: fatal error: WS2812_Definitions.h: No such file or directory

include "WS2812_Definitions.h"

^

compilation terminated.

exit status 1 Error compiling for board Arduino/Genuino Uno.

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Where did you put the file "WS2812_Definitions.h" ?