Do Until Loop - Transferring data from several workbooks to a Master workbook

Hello all,

I am trying to transfer data from several workbooks (8 at the moment) to a single Master Workbook.

All the headers are the same in all workbooks, the only difference are the number of rows, thus the use of Do Until to identify the last populated row

I have tried using Do Until Loop but I always end up copying and pasting in the same row in my Master workbook.

Here is the code, I see where the problem is but I cannot correct it. (my guess is Range C9 in the loop, it should be dynamic instead but i cant figure out the code to do this)

PS: I'm a beginner in VBA and have always struggled with it

sub import()

Workbooks.Open Filename:="C:Source 1.xlsx"
  
    Range("c9").Select
     
    Do

        Range(Selection, Selection.End(xlToRight)).Select
                Selection.Copy
                ActiveWindow.ActivateNext
                    Range("C9").Select
                    ActiveSheet.Paste
                    
                    ActiveWindow.ActivateNext
                    ActiveCell.Offset(1, 0).Select
                    
        
        ActiveCell.Offset(1, 0).Select

      Loop Until IsEmpty(ActiveCell)
      
            ActiveWindow.ActivateNext
            ActiveCell.Offset(1, 0).Select
            
    Windows("Source 1.xlsx").Activate

    ActiveWindow.Close

end sub