Change the "Opacity" or "Composite" mode of the spark layer to Screen . This makes the black background disappear, leaving only the glowing sparks.
If your practical fire looks weak, layering a few spark overlays can make it look more intense and dangerous. fire sparks free download
These sites are excellent for royalty-free stock footage. Search for "fire sparks" or "embers" to find 4K clips with black backgrounds. Change the "Opacity" or "Composite" mode of the
Drag your spark clip into your timeline on the layer above your main footage. fire sparks free download