Creating Fire effect (the concept)

Tip: use the "add" layer blend mode Tito get the fire/ flame effect.

Follow below steps:
1. Use the flame brush and make Radom scattered strokes with orange color

2. Then lock the transperancy of the layer and paint some random strokes of red color. ( since the transperancy - pixels - are locked, red only happens on top of orange color)

3. Duplicate the layer

4. Change the background to black.

5. Most important: now change the top layer mode to "add". You see the magic :-)

6. Using airbrush paint some glow affect in a bottom layer.

7. You are done!