if script.Parent:FindFirstChild("IsExploding?").Value == true then
local explosion = Instance.new("Explosion")
explosion.BlastRadius = 60
explosion.ExplosionType = Enum.ExplosionType.NoCraters -- damages terrain
explosion.Position = Part.Position --Put your part's position here
explosion.Parent = script.Parent
The script I send and the script you have listed are two different things.
One looks for the value to change and then it fires the function, the other just does a one-time check to see if it is true. If you have not tested my script then you should give it a try because it should work. If not please provide more details as to what errors you might be receiving and where things are located at in the explorer tab.