How can I make this Explosion?

How do you make it so if something Explodes; there becomes a Sphere that basically appears at the explosion? I only know how to do the instance.new I cannot mannage to exactly make the two functions cooperate together.

You don't need to make "two functions cooperate", you just write your code like you normally would. You probably are looking for something like this maybe?

function explode(pos) -- I'd make a function for it
	local sphere = Instance.new("Part")
	sphere.Shape = Enum.PartType.Ball
	sphere.CanCollide = false
	sphere.Anchored = true
	sphere.Size = Vector3.new(25, 25, 25)
	sphere.Transparency = .7
	sphere.BrickColor = BrickColor.Yellow()
	sphere.CFrame = CFrame.new(pos)
	local exp = Instance.new("Explosion")
	exp.Position = pos
	sphere.Parent = Workspace
	exp.Parent = sphere
	Game:GetService("Debris"):AddItem(sphere, 3)
end

-- Ex:
explode(Vector3.new(0, 0, 0))

Part.Touched:connect(function() -- A usage example
	explode(Part.Position)
end)