1.) Open up SF --> Sounds --> Add from MPQ. Look in the lists on the side. I haven't played Racoon City so thats about as close as I can get with the infromation you get me.
2.) If player x brings one unit x to location x, display text [11+ Enters here]Text, set switch 'On,' Preserve Trigger. Now make another trigger...if switch 'On' is set, player x brings exactly zero units to location x, display text [11+ Enters].
3.) Center a location on the players main unit (Hero, w/e [See
this tutorial]), then when player x brings unit x to location x, create x number of x units on the location that is following the unit.
Oh, and, there is no skill level anymore

.