Block not changing position?

So I'm trying to get it so it changes automatically so say you move your mouse then it moves, It doesn't do that it just stays still. I'm also trying to get it to change block type when it's changed,

local last = "Slab"

script.Parent.Parent.MaterialPicker.Placing.Changed:connect(function()
    if script.Parent.Parent.MaterialPicker.Placing.Value then
        repeat
            local GetMaterial = script.Parent.Parent.Refrences:WaitForChild(currentType)
            wait(.1)
            --If diffrent then change block
            if script.Parent.Parent.Refrences:WaitForChild(currentType).Name ~= last then
                Player.Character[last].Parent = script.Parent.Parent.Refrences
                last = GetMaterial
            end
            --
            GetMaterial.Parent = Player.Character
            GetMaterial.Transparency = .6
            GetMaterial.BrickColor = BrickColor.new(script.Parent.Parent.MaterialPicker.Colors.CurrentColor.Value)
            local material = script.Parent.Parent.MaterialPicker.MainFrame.CurrentMaterial.Value
            local x = math.ceil(Mouse.Hit.p.X)-2
            local z = math.ceil(Mouse.Hit.p.Z)-2
            x1 = x%4
            z1 = z%4
            x2 = x + (4 - x1)
            z2 = z + (4 - z1)
            GetMaterial.CFrame = CFrame.new(x2, round(Mouse.Hit.p.Y, .2)+.3, z2)
            GetMaterial.Material = Enum.Material[material]
            GetMaterial.CanCollide = false
            part = GetMaterial
        until not script.Parent.Parent.MaterialPicker.Placing.Value
    end
end)