Answer
The way I understand your issue is this. You have a Ford that has a PATS computer, but you want to replace the door and ignition lock cylinders with lock cylinders from another vehicle.
Note that if you change the ignition lock, you will have to either change the door locks as well or have a key cut that will be compatible with the door and ignition keys. This is hard to do with Ford since their keys are only 10 cuts long and the three cuts in the middle of the key overlap. This means that the first six cuts from the tip of the key (the part going into the cylinder) are used for the ignition and the first six cuts from the head of the key (the handle that you hold) are used for the door. This creates an overlapping key system that is hard to match to a different set of locks unless you buy them altogether.
The new key system MUST use PATS keys. You can perform most of the work yourself, but you have to have the "new" keys programmed at a dealership or locksmith. To replace the ignition cylinder, you must turn the key to the run position and use a long punch type tool to insert into the hole at the bottom of the steering column just underneath the ignition switch. You should be able to push the pin in that is holding the cylinder in and pull the cylinder out by the key. Then you put the "new" ignition in the run position and slide it into the steering column. Turn the key to "off" to lock the cylinder in place.
To replace the door locks is slightly more complicated because you have to remove the door panel and then you have to remove the metal clip that holds the lock in place. This requires small hands and a lot of flexibility in some cases to be able to fit in the proper area.
Once you have the new cylinders in place and the keys are working mechanically, you have to have a locksmith (recommended) or Ford dealership program the keys to the vehicle. You will not be able to program it on your own unless you have the computer to do so. I would use a locksmith only because they normally have the ability to come to you in a van, whereas a dealership will require you to bring the vehicle to the shop. Since you can't drive the vehicle now (the new PATS key isn't programmed to the computer yet), you would have to have it towed to the dealership. Depending on the cost of towing and what the dealership would charge you to program the key, it will probably be cheaper to have a locksmith come to you and program the key with a lot less hassle and money.