How to make NPC's use abilities?

We worked it out on discord. Here's the code if anyone wants to try it out for themselves: I tried to add comments to explain, but comment if you have any more questions.

local effects = game.ReplicatedStorage.Effects
local NPC = script.Parent

function useFireball(playerToAttack)
	--create the fireball
	local fireBall = effects.MagicSkill:Clone()
	fireBall.Position = NPC["Right Arm"].Position
	fireBall.Parent = workspace
	
	--weld the fireball to the npc's hand and destroy it after .1 seconds to give the effect that it came from the npc's hand. 
	local weld = Instance.new("WeldConstraint", fireBall)
	weld.Part0 = fireBall
	weld.Part1 = NPC.RightArm
	wait(0.1)
	weld:Destroy()
	
	
	--give the fireball a velocity.
	--shooting at the direction of the player's head
	local velocity = Instance.new("BodyVelocity", fireBall)
	velocity.Velocity = CFrame.new(fireBall.Position, playerToAttack.Character.Head.Position).LookVector * 100
	
	--create an event that explodes the fireball when it touches a character
	fireBall.Touched:Connect(function(hit)
		local explosion = effects.Explosion:Clone()

		if hit:IsDescendantOf(NPC)or hit:FindFirstChild("ParticleEmitter") then return end
		
		explosion.Position = fireBall.Position
		fireBall:Destroy()
		explosion.Parent = workspace
		
		if hit.Parent:FindFirstChild("Humanoid") then
			hit.Parent:FindFirstChild("Humanoid"):TakeDamage(30)
		end
	
		wait(5)
		explosion:Destroy() 
	end)
end
 
while true do
	wait()
	--every 1/30th of a second,
	--loop through the list of players in game
	for i, player in pairs(game.Players:GetChildren())do
		--if that player has a character...
		if player.Character then
			--get the character's distance from the npc
			local distanceFromNPC = (NPC.Torso.Position - player.Character.UpperTorso.Position).Magnitude
			
			--if the player is 100 studs or closer to the npc
			if distanceFromNPC <= 100 then
				--have the npc attack the player with a fireball
				useFireball(player)
				wait(5)
			end
		end
	end
end