Can i get some help with vectors and velocity?

Im trying to get my "Bul2" to go up and forward at the same time, how can i do this?

local FG = script.Parent
local Handle = script.Parent
local Bul = game.ServerStorage.FlareBull

local function Onclick()
    local Bul2 = Bul:Clone()
	 Bul2.Position = Handle.Handle.Position
	 Bul2.Velocity = Handle.Handle.CFrame.XVector * (300)
	 Bul2.Velocity = Handle.Handle.CFrame.YVector * (300)
	 Bul2.Parent = workspace
wait(4)
    Bul2.Anchored = true
    Bul2.ParticleEmitter.Rate = 0
    Bul2.Transparency = 1
wait(10)
    Bul2:Destroy() 
end

FG.Activated:Connect(Onclick)

Do note that BasePart.Velocity takes a Vector3. Lines 08 and 09 rewrite over each other and that results in the part moving in just one direction. You should just do Vector3.new(300,300,0).