Macro Auto run

[Sazza]

Hi Guys,

New to Macros and VBA but ...

I have a simple Macro to hide rows if a cell value is NO called "Sheet1.ZeroTest"

this works but i have to run macro manually each time

So i have looked around and see i need a Worksheet change function to call this automatically if the cell contents change to 'YES'

I have something like this

Private Sub Worksheet_Change(ByVal Target As Range)
 If Intersect(Target, Me.Range("C12")) Is Nothing Then Sheet1.ZeroTest
End Sub

But my problem is i dont know where to put this in order for it to work...

I have the Macro in Sheet1, how do i add the auto run to sheet1 too

thanks
Saz