All you need is:
- flash CircuitPython
- put the neopixel library in lib folder
- replace code.py that stores on board with that, which placed here (look for your board name)
- connect NEOPIXEL supporting smart LED (W2812)
- change port which connected to NEOPIXELs (there may be nore than 1, much more...)
This plate has W2812 onboard, so you just need to solder or connect any other way 2 contacts above onboard LED
W2812 LED already connected to GP23 port, so you don't need to do anything at first.