To load the Tornado add-in

After saving the file on the hard disk, unzip the Tornado.zip file.  Save the Tornado.xla and the Tornado.chm files in a convenient directory.

Run Excel and load the add-in by selecting Tools | Add-ins... (see Figure 2)

Figure 2

Click the Browse... button, and locate and open the Tornado.xla file saved in the previous step.  Ensure that the checkbox next to the Tornado diagram creator entry is checked (see Figure 3).

Figure 3

The Tornado diagram add-in is now available for use.