I need help with some explosive stuff?

?

local a = script.Parent.Parent
local b = script.Parent

if b.Value<=0 then
local Explode = Instance.new("Explosion")
local Sound = Instance.new("Sound")
Sound.SoundId = "rbxasset://sounds/collide.wav"
Sound.Parent = Explode
Explode.Position = a.Position
Explode.Parent = a
Sound:Play()
wait(0.5)
a.Parent:Destroy()

I would like to get this script working, but I haven't worked on scripting fully. What the script does is when someone makes the value above the script go under 0 it should explode, and then remove the brick.