Take a look
here
Effects will behave in the similar way as images do, use eff.Create function like image function:
1
effectvar = eff.Create("flare", player(id, "x"), player(id, "y"), 0, 50, 1, 255, 128, 0)
Otherwise, you won't be able to edit your effects (if it is needed of course). All effects are being removed on each roundstart. You have two examples to see how it works:
1st - adds effect when player spawns;
2nd - adds color effect to grenades (purple to HEs, light-yellow to flares and white to flashbangs);
3rd - highlights all medikits on the ground (CS1.6 style)