You'll need to consult your owner's manual for the exact steps. The procedure often involves inserting the key into the ignition, cycling it through various positions (ON and OFF), and then pressing buttons on your key fob within a certain time window.
If you don't have the owner's manual, you can often find a PDF version online by searching for "[Year] Ford Excursion owner's manual" on Google or your preferred search engine. Alternatively, you can check forums dedicated to Ford vehicles and the Excursion; someone there might have instructions or videos illustrating the process. A Ford dealership service department can also provide the information, though they may charge for the service.
