Moving Particles on a line

Hi everyone

I’m trying to create an effect of fire moving in a downward direction and then plateau in line with the ground in an outwards direction (like eg. when a rocket launches and how the fire hits the ground) I have played around alot with the settings but i don’t seem to be get the effect I’m looking for. Some sites say I should move the emitter on a path but doesn’t really tell me how, Is there another way to do this or if someone could please give me some guidance with this.

Thank you