Example:
SOUND* mywhoosh = "whoosh.wav"
var sndhandle
sndhandle = snd_play(mywhoosh,100,0);

Also please note that the sound is played on the same side it is emited on.
eg: If the sound source is to the left of the plyer, It will come sound out on
the left speaker only. The only other way around this is to use
ent_playsound instead.