I don't have much of an overview but I can tell how character selection would be set up:
The idea is a very simple and straightforward character sheet. You would give their vital stats such as age sex, etc.
You would also pick a profession such as surgeon, banker, college student, etc, and some skills like the guy is good at parkour (free running), or breaking and entering these things are really up to you as they will have an impact on how the group does as a whole.
The character would also have some personal effects that he managed to grab before the zombies attacked. This would help explain their backstories to the audience.
Actually as I'm writing this I have a story developing in the back of my head and a premise also. I'll have it up within a day or so.