object detection

I am new to python and it’s my first time using the OpenMV cam. For my project, I need to detect tennis balls and then send data to an Arduino however when I try to use the OpenMV youtube videos or its own IDE examples they all direct me to GitHub pages that don’t exist anymore. My question is how to implement a NN on openmv. I was wondering if any of you wonderful people could help me, like are there any helpful sources?. Thank you in advance.