Can't add scenes to Build Settings...

Hi,

this is a noob question, i know, but i never used Unity before, so I ask...

Anyway, i'm developing an fps game, and when i go to build setting it says something about Flash Player, and i don't even know how to add some scenes to build setting, because of this little problem. I hope you can help me, and sorry for my bad english. (I'm Italian :D )