This is a blinking LED activity as the intro for Arduino Code programming.
Arduino is both software and hardware. Right there, you can control the design.
There are two built-in functions in Arduino Code:
void setup and void loop.
void setup is where you tell the computer whether
an electronic component being programmed is an
output device. Other initial setup can be
done here, like, the initial mode of an LED
is turned on.
void loop is where the execution of programs
happen.
Take note of the word void. A void type
of function will simply execute all the commands
and will not return any value. Other functions
which are not void can return values.