Mapping a button press to keyboard button press/Keyboard Library not working

[GeneralJMan]

Hello, I am trying to build a simple controller, but I'm just starting by mapping one button. I need to figure out how to map a button press to a key on the keyboard.

I don't really know how to do this. I've tried to experiment with the keyboard, but whenever I load the library it doesn't recognize it.

[johnwasser]

Looking in the bottom right corner it says you are trying to compile for an Arduino UNO. The Keyboard and Mouse libraries only work on Arduino models with a 32u4 processor, like the Arduino Leonardo and Arduino Pro Micro. See the library documentation.