Arduino LED - Complete Tutorial - The Robotics Back-End

Arduino IDE: for Loop

Arduino programming tutorial for beginners with examples

Arduino Timing Methods With Millis()

Doing multiple timed things with Arduino: Unleash the millis()! - Programming Electronics Academy

Arduino millis() - The Beginners Guide to multi-tasking with Arduino using millis() - Programming Electronics Academy

Making the Arduino Blinking LED Project (a Complete Tutorial)

Simple LED based Projects using Arduino-with Circuit Diagram and Codes