I’m putting together a very small-scale project on an Arduino Uno and simply need a clean, well-commented sketch that switches an LED on and off. No elaborate libraries or peripherals—just straightforward LED control that compiles in the current Arduino IDE and can be uploaded over the standard USB cable. What I expect from you • An .ino file that drives either the onboard LED (pin 13) or an external LED on any digital pin I can redefine at the top of the sketch. • Clear inline comments explaining each step so a beginner can follow the logic and reuse the code in future experiments. • A short read-me noting the exact IDE version you compiled with and the wiring diagram if you choose an external LED. That’s all—simple, reliable, and ready to run.