Case Select VBA Depending on cell i click

[Legacy 185509]

This is my current code
I don't know where to put this code but i have it undr Sheet1 tab (View Code)
here is what I am have there

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
     
    Select Case Target.Address
         
    Case "$A$11"
        Sheets("Sheet2").Select
        Range("A2").Select
        ActiveCell.FormulaR1C1 = Range("S12")
        
    Case "A12"
               Sheets("Sheet2").Select
        Range("A2").Select
        ActiveCell.FormulaR1C1 = Range("S13")
    
     Case "$B$21"
               Sheets("Sheet3").Select
        Range("A2").Select
        ActiveCell.FormulaR1C1 = Range("S2")
    End Select
End Sub

if user click's on Cell C11 on sheet1, in Sheet2 Cell A1 it will type some formula or take the range of S2

 

[Scott Huish]

If you have it in Sheet1 code, it will function on Sheet1.

But there is no need to do all that Selecting:

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
     
    Select Case Target.Address(0, 0)
         
    Case "A11"
        Sheets("Sheet2").Range("A2") = Range("S12")
        
    Case "A12"
        Sheets("Sheet2").Range("A2") = Range("S13")
    
     Case "B21"
        Sheets("Sheet3").Range("A2") = Range("S2")
    End Select
End Sub

You will need to clarify what you mean by that last sentence. What is the condition for either putting in a formula or the value from S2?