You must at first select those cells, if you want to complete a function of a group cells. If you select a cell your selected cell will highlight a color.
1. First, click A1 cell.
2. Press F8 function key from your keyboard.
3. You see the “EXT” on the status bar in the right lower corner of the screen.
4. Now, click F11 cell.
5. Your excel worksheet A1 to F11 will be select.
6. If you want to deselect it, at first press Esc button from your keyboard and click anywhere on the worksheet.