How do you keep all 4 characters alive on Heavy Rain?

Mostly for the trophy, but I want them to survive just out of the fact that it will make me content (i don't really want to see 4 good characters die =[ ) I know you have to keep madison, ethan, shaun, and the detective alive. How do I do this? Please make it simple, I've tried everything and it's all so confusing to understand. Thanks!!