[SCRIPT] Entity that activates a script.. HELP

[MortenAbra]

Hey.
My problem is, when you assemble a entity, a script area must be createded behind him, and when he walks into the script area, a prop should activate, and then fade. How do i do that?
"The last part, with the corpse, is not the problem"

Thanks for the help.

MortenAbra.