Make a "description.ext" in the folder of the mission (your_ofp_directory/users/your_username/missions/name_of_mission).
class CfgSounds
{
sounds[] = { };
class bite
{
name = "bite";
sound[] = {"bite.ogg", db+40, 1.0};
titles[] = {1, "" };
};
};
Save the sound as an ogg file named bite. (ogg requires a conversion, use a special program to do this)
In your mission, you can put in the On Activation field: playsound "bite"
Hope this helps and works