Sheet Change Event Dubuggin: Restrict Cell Values toand Changing cells based on input

Cannot debug worksheet change even below. If invalid entry entered change event is inoperable unless workbook closed and reopened. Goal is to
1. Limit entries to VBA Array PTest (trying to avoid Data Validation, if possible?) 2. want to change column F to reflect date that corresponds to value inserted in PTest.

Is this doable? I cannot even debugg to test, any suggestions?

    Build
    Application.EnableEvents = False
    
    If Target.Column = 3 And Target.Row = TestsTaken + 7 Then
        item = Cells(Target.Row, 3)
        If IsError(WorksheetFunction.Match(item, PTests, 0)) Then
            MsgBox "Please Insert Valid PTest"
            Cells(Target.Row, 3) = vbNullString
        Else: x = WorksheetFunction.Match(item, PTests, 0)
            
        Cells(Target.Row, 2) = Date + Time
        Cells(Target.Row, 1) = Target.Row - 6
        Cells(Target.Row, 3).Font.Color = 16711680
        Cells(Target.Row, 1).Resize(1, 2).HorizontalAlignment = xlCenter
        Cells(Target.Row, 6) = Application.Index(PTests, x, 0)
        End If
    End If

    TestsTaken = Sheet3.Cells(Distance, 1).End(xlDown)
    Build
    Application.EnableEvents = True