You will need two animations, one will be the fireball in motion and the other will be the animation for when the projectile hits your opponent.
Once you've got these, you can code in the projectile like so:
[State ?, 1]
type = Projectile
trigger1 = Whatever you want it to be... like maybe AnimElem = 1
projanim = the animation of the projectile in motion
projhitanim = the second projectile animation mentioned above
projpriority = 1
projheightbound = -240, 100
projedgebound = 100
projscreenbound = 100
projshadow = -1
offset = 50, -10
sparkno=s7000+(random%8)
sparkxy = -20, -20
velocity = 3
attr = S, SP
damage = 12,4
animtype = heavy
guardflag = MA
hitflag = MAFDP
pausetime = 17,17
hitsound = 15,1
guardsound = 15,2
ground.type = Low
ground.slidetime = 25
ground.hittime = 25
ground.velocity = -6
air.animtype = Back
air.velocity = -4,-6
air.juggle = 3
air.fall = 1
down.velocity = -4,-6
down.hittime = 30
down.bounce = 0
Keep in mind that you can change any of those numbers you want
Now then, you'll need to define a command in your CMD file to activate the projectile; this is the same as coding any other command. Make the command call the stateno in which your character throws the projectile.
Play around with it and tweak the values until you like it.
I hope this helps!
