Who to properly stack hats with UPS hat / where do you place it?

I tried to search for this but did not get much.

I think the primary question is where should the power UPS HAT go? Directly on top of Raspberry pi, or on top of other HATs?

I am hopeing to use it with PI Plates Thermoplate ( THERMOplate – Pi-Plates ).

Where should I place it?

FYI (it will be used with solar powered 12V system).

Thanks Ed