Getting started with collision

Hi folks
I’m looking to be pointed in the right direction for a tutorial or page or anything that could help me out.

Have a character using the mecanim system that runs around nicely. I can also now get this character to run into a stack of boxes and cause them to fall over. So far so good. What I am looking to do however is create a building in a pre and post hit state, so on hit, I switch out the building and apply the ridged body physics to the parts of the post hit state building.

I am unsure where to start looking and any help would be greatly appreciated.

Thanks and happy new year to you!

Na ha! Seems I should have been searching for destruction. Not to worry, thanks if you read it!