Blinking led,it is the easiest circuit.
you just need any version of Arduino, in this I used Arduino nano.
Step 1: Step1: Writing the Code
you should have the Arduino program to write your code, you can download it from Arduino website it is an open source program.
At the first, I used a digital pin and define it in the setup loop as an output pin.
Then, I write to connect the led with power for one second and turn it off for another second and so on.
Step 2: Step2: the Final Circut
After writing the code, I should connect the Arduino with the laptop to upload your code on the Arduino.
And then connect your circuit.
watch the video to see ho it works.