Beginner in need of help !!

[Amoque]

Not sure how much help you need. I'm assuming you know input/ output, high/ low...

Google "Pull down switch" and see how the level goes from high to low when the button is pressed (there is a pull up as well); use standard input technique to read the level change when the switch is pressed. To control the LED output, I think an if/ then will work well:

If Button press = 0 and LED = off then [turn on LED]
If Button press = 0 and LED = on then [turn off LED]

You should also look at "debounce" as there is some issue to mechanical switches.

Also, without some programming to limit the speed, the switch will turn the LED on/ off very quickly. A pause will work (to give the user time to release the button) or, you can look for a "1" on the switch (released) before allowing another button press to register.

HTH,