Addon scripting information/tutorial?

[Addon scripting information/tutorial?]

Hello all,
I am having issues with this control structure:

if (_randomselectX >= 8) then {

_unit addEventHandler ["Fired", {_soundPath = [(str missionConfigFile), 0, -15] call BIS_fnc_trimString; _soundToPlay = _soundPath + "sounds\contact1.ogg"; playSound3D [_soundToPlay, (_this select 0), false, getPos (_this select 0), 20, 1, 150]}];

_unit addEventHandler ["FiredNear", {_soundPath = [(str missionConfigFile), 0, -15] call BIS_fnc_trimString; _soundToPlay = _soundPath + "sounds\alert1.ogg"; playSound3D [_soundToPlay, (_this select 0), false, getPos (_this select 0), 20, 1, 150]}];

_unit addEventHandler ["Dammaged", {_soundPath = [(str missionConfigFile), 0, -15] call BIS_fnc_trimString; _soundToPlay = _soundPath + "sounds\hit1.ogg"; playSound3D [_soundToPlay, (_this select 0), false, getPos (_this select 0), 20, 1, 150]}];

_unit addEventHandler ["Explosion", {_soundPath = [(str missionConfigFile), 0, -15] call BIS_fnc_trimString; _soundToPlay = _soundPath + "sounds\explosion1.ogg"; playSound3D [_soundToPlay, (_this select 0), false, getPos (_this select 0), 20, 1, 150]}];

};

and for whatever reason i cannot seem to start my own topic...

I need to somehow cause the event handlers to only activate one time or delay repeat activation 300 seconds... either would work... any help would be appreciated or a link to a tutorial or something similar else where
Thanks