I started with the manuals for all the solar components.
They all give their requirements, for example
- clamping zones of panels,
- cable/breaker size for inverter
- number of batteries
- PV disconnects and fusing
- etc.
The list is long and changes for every component depending on make and model. The pylontech battery firmware discussion should be red flag for all of us…
Then you look at other installs for all the good ideas and work from there.
You will need a CoC and so need your electrician to be comfortable as well.