Place The Neopixel.mpy File In The “Lib” Directory On The Pico:

neopixel.mpy_Download
"""
NeoPixel example for Pico. Turns the NeoPixels red, green, and blue in sequence.
REQUIRED HARDWARE:
* RGB NeoPixel LEDs connected to pin GP0.
"""
import time
import board
import neopixel

num_pixels = 1  #Number Of Neopixels Connected

pixels = neopixel.NeoPixel(board.GP28, num_pixels)  #GPIO Number Of Pico Or Board
pixels.brightness = 0.02  #Change Brightness Of The RGB

while True:
    pixels.fill((255, 0, 0))
    time.sleep(0.5)
    pixels.fill((0, 255, 0))
    time.sleep(0.5)
    pixels.fill((0, 0, 255))
    time.sleep(0.5)