Update README

Author: andrewgdotcom

README.md

@@ -81,7 +81,7 @@ Hold down the "Prog" key in the top left corner of your keyboard, until the comp
 
 # Start to customize the firmware
 
-You can customize your keyboard's key layout and LED effects by modifying the `Model01-Firmware.ino` file in the same directory as this README. Model01-Firmware.ino is a computer program written in 'Arduino C'. You can find documentation about Arduino C at https://arduino.cc.
+You can customize your keyboard's behaviour by modifying the `Model01-Firmware.ino` file in the same directory as this README. Model01-Firmware.ino is a computer program written in 'Arduino C'. You can find documentation about Arduino C at https://arduino.cc. The keyboard layout is defined in the include file `keymaps.h`, which consists mainly of C preprocessor macros.
 
 
 # Updating the firmware and libraries