Base that SFX from a unit in Object Editor.
Select any unit in the Object Editor and go to Art - Model File and change it to any SFX you want, you can even scale the size of your "SFX" just edit the Art -Scaling Value
Okay now, since your "SFX" is a unit, you can use this to pause the effect appear (just need a right timing for each of them though);
Animation - Change (Last created unit)'s animation speed to 0.00% of its original speed