How to script a death fall and respawn?

I really need to know how to make a script which will make my character, which is a First Person Controller (Unity's prefab) die when it falls off one of the roof tops I've made, and when hitting the ground, the player will respawn at the original spawn point. Is this possible? Can it be done all in one single script? Also, if you could help me too, I need a script to go on to the next level when reaching a "button", I mean, when you step on it, you go on to the next scene. If you could give me these 2 scripts, you'd be saving my life :D Thanks a lot! Btw, I've already tried triggers for the second script, this isn't working for me at all.