99 expedition ignition switch

is there any instructions on how to change the ignition switch

They are located on the steering column. Generally just past the mount where it bolts to the dash. They have a rod from the key tumbler that goes to the ignition switch. Normally they have tamper proof torx bolts. The parts store will sell a set if you don't have one.
I disconnect the battery neg. after the seat is moved all the way back then loosen the two bolts holding the wheel about all the way. You may have to remove some covers. Buy a new switch before you start so your sure what you are looking for. Their will be a color difference in the metal when you remove the old switch. Make sure your new switch is exactly the same or you will have to adjust it. Not as easy as it sounds.