Steps to filter for unique combinations of cells in Excel:

1. Select the entire range of data that you want to filter. In your case, that would be columns D, E, and F.
2. Click on the "Data" tab in the ribbon at the top of the screen.
3. Click on the "Advanced" button in the "Sort & Filter" section.
4. In the "Advanced Filter" dialog box, select the "Copy to another location" option.
5. In the "Copy to" field, select a cell where you want the filtered data to be copied. This can be on the same sheet or a different sheet.
6. Check the "Unique records only" box.
7. In the "List range" field, enter the range of cells that you want to filter. This should be the same range that you selected in step 1.
8. In the "Criteria range" field, enter the range of cells that contains the criteria for the filter. In your case, you can leave this field blank since you want to filter for unique combinations of cells.
9. Click the "OK" button to apply the filter.

Excel will now filter the data based on the unique combinations of cells in columns D, E, and F, and copy the filtered data to the location that you specified in step 5.