Trying to code Arduino with neopixel
Adafruit has an excellent tutorial.
Check this out on project hub:
What have you tried to do this?
I think the other replies are missing the point here. The existing WS2812 libraries are not compatible with the RP2040 chip. You can run a strip with the PIO state machine pins, but my understanding is that this is not yet supported in an Arduino environment.
You might be able to do it if you install one of the Python variants but the you loose access to all the stuff that makes it an Arduino and not a Raspberry Pi controller.