You just need these components :
- a KeyDuino (https://www.elecrow.com/keyduino-p-1620.html)
- a RGB WS2812 LED strip (https://fr.aliexpress.com/item/1m-4m-5m-WS2812B-Smart-led-pixel-strip-Black-White-PCB-30-60-144-leds-m/32351194166.html)
For the supply, if you want to use more than 8 LEDs (~500mA at full power, too much for the KeyDuino & basics USB), you will need an external power 5v supply like this one
and follow the wiring at 1:52 & 2:20 from the video.
Maybe you can found directly on the computer a 5V supply that can delivery more current than an USB and use it instead of an external supply