Insert value to cell

I need to insert "1" in column C on the Emp_tmp sheet.  Not sure how to do that if someone could help.  I also think the Then last row = 0 is inserting zeros all down the whole sheet.  I do not want that ..  is there a way to take out?  I am not sure what it is doing....Thank you

Dim lastCol As Long, lastRow As Long
Application.ScreenUpdating = False
 
    With Sheets("Emp_tmp")
        lastRow = .Cells(.Rows.Count, "A").End(xlUp).Row
        If lastRow = 1 And .Cells(1) = "" Then lastRow = 0
        .Cells(lastRow + 1, "A").PasteSpecial Paste:=xlPasteValues, _
            Operation:=xlNone, SkipBlanks:=False, Transpose:=False
    End With
End If
End Sub