First thing you should do is get the location of the player that triggers the event that activates your sfx code

Syntax: es_getplayerlocation <var x> <var y> <var z> <userid>

WCS already has the vars for x,y,z set so you dont have to worry about that

es_getplayerlocation wcs_x1 wcs_y1 wcs_z1 event_var(userid)

Now that you have stored the players x,y,z coords you can say where to make the effect
i like to use est_effects, as of version 4.18 there are 12 different est_effects
with  different syntax for each

]-------------------
] est_effect
]-------------------

] est_effect 1
EST Syntax : est_effect [ArmorRicochet] <player Filter> <delay> <model> (position <X> <Y> <Z>) (direction <X> <Y> <Z>)

] est_effect 2
EST Syntax : est_effect [BeamEntPoint] <player Filter> <delay> <model> <start userid> <end userid> <life> <width> <end width> <Red> <Green> <Blue> <Alpha>

] est_effect 3
EST Syntax : est_effect [BeamPoints] <player Filter> <delay> <model> (start <X> <Y> <Z>) (end <X> <Y> <Z>) <life> <width> <end width> <Red> <Green> <Blue> <Alpha>

] est_effect 4
EST Syntax : est_effect [BeamFollow] <player Filter> <delay> <model> <userid> <life> <width> <end width> <time to fade> <Red> <Green> <Blue> <Alpha>

] est_effect 5
EST Syntax : est_effect [BeamRing] <player Filter> <delay> <model> <userid> <end index> <life> <width> <spread> <amplitude> <Red> <Green> <Blue> <Alpha> <speed>

] est_effect 6
EST Syntax : est_effect [LargeFunnel] <player Filter> <delay> <model> <x> <y> <z> <reversed>

] est_effect 7
EST Syntax : est_effect [Smoke] <player Filter> <delay> <model> <x> <y> <z> <scale> <framerate>

] est_effect 8
EST Syntax : est_effect [MetalSparks] <player Filter> <delay> <model> <x> <y> <z> (towards <x> <y> <z>)

] est_effect 9
EST Syntax : est_effect [GaussExplosion] <player Filter> <delay> <model> <x> <y> <z> (towards <x> <y> <z>) <type>

] est_effect 10
EST Syntax : est_effect [BeamRing] <player Filter> <delay> <model> <x> <y> <z> <start radius> <end radius> <life> <width> <spread> <amplitude> <Red> <Green> <Blue> <Alpha> <speed>

] est_effect 11
EST Syntax : est_effect [GlowSprite] <player Filter> <delay> <model> <x> <y> <z> <life> <size> <brightness>

] est_effect 12
EST Syntax : est_effect [PhysProp] <player Filter> <delay> <model> (pos <x> <y> <z>) (angle <x> <y> <z>) (velocity <x> <y> <z>) <subtype> <flags> <randomize>

es est_effect 11 #a 0 sprites/lgtning.vmt server_var(wcs_x1) server_var(wcs_y1) server_var(wcs_z1) 1 1 255