When I bought my first board in September 2023, just a month later I was building my first 15S3P battery.
Having some basic knowledge of electronics and soldering, the task didn’t seem overwhelming as long as everything was done pragmatically.
So I began by creating a diagram to avoid mistakes, and I wanted to share it with you.
Thanks to Spencer Hiren and Frédéric DV (a pioneer of VESC Onewheel in France) for their help. 
You can also download the PDF version here : PDF