Hi there!

Here are the steps to insert the 'therefore' symbol into your Excel spreadsheet:

1. Click on the cell where you want to insert the symbol.
2. Go to the Insert tab in the Excel ribbon.
3. Click on the Symbol button in the Symbols group.
4. In the Symbol dialog box, select Arial Unicode MS as the font.
5. Scroll down until you find the 'therefore' symbol (it should be around the middle of the list).
6. Click on the symbol to select it.
7. Click on the Insert button to insert the symbol into the cell.

Alternatively, you can also use the keyboard shortcut to insert the 'therefore' symbol:

1. Click on the cell where you want to insert the symbol.
2. Press the Alt key and type on the numeric keypad.
3. Release the Alt key and the 'therefore' symbol should appear in the cell.