the wait(100) problem?

currently im working on a project. when you click a prick. it will take 100 seconds to delete it completely. now of course there would be a gui above it saying how many seconds are left. by a gui i mean a billboard gui. now i made this script :

script.Parent.ClickDetector.MouseClick:connect(function()
    script.Parent.Parent.CircleOfJoy1111:Destroy()
end)

but i need to know what to put under it. im a bit confused with lua so i need to know where to put the wait 100. would it be like this?

(In english verion)

text 100 wait 1 text 99

(so on)

You should use a for loop for this.

for i=100, 0, -1 do
	BillboardGui.Text = i (Change this to the directory of the GUIs TextLabel)
	wait(1)
end

Every time the loop is run, i will go down by 1 every second until it is at 0. It will display the value of i every time the loop is run.

If you didn't want to show a "clock" ticking down then wait(time in seconds) would suffice as the other answerer has said.