You are confused because you didn't read the WHOLE bulletin and didn't refer to the supplied table to see what type of PATS systems is used by the F-series trucks. The excerpt you posted is for the Type "A" system which has never been used in any of Ford's F-series vehicles.

Bottom line: You either need two programmed key to add more or you need a properly equipped dealer of locksmith.

If you have only one PATS key, there is a way to avoid the large expense of getting additional PATS keys. It somewhat compromises security, so you are at a bit increased risk of theft, although no greater than a remote starter that uses a PATS bypass module with a live key inside. If you choose to accept this risk, proceed as follows:

1) Take your existing key somewhere and get at least two generic flat keys cut to the same key cut.
2) Remove the transceiver ring from the ignition cylinder.
3) Position your working PATS key inside the transceiver ring and secure it with plastic cable ties.
4) Secure the ring/key assembly up inside the dash in a spot than makes it difficult to get to easily.
5) Reassemble everything and use the generic keys for everything. The hidden PATS key will satisfy the security system whenever you start the vehicle.