Wow you are in for a headache there. That actuator is bolted to the inside left lower part of your door for the left door. Inside lower right for the right door. You will need to remove the door panel, have the window in the all the way up position, and the window regulator is going to make you curse for more space to work trying to get that little sucker out of there. It's held in place by a few 10mm nuts i believe, you need to disconnect the actuator door locking post/ bar from the door latch itself, unclip the electrical connector, unclip it from the door handle, and maybe just maybe it won't be to bad. Every time at the salvage yard where i work, someone needs one, all 7 of us flip a coin to see who get's the pain of pulling it out, and our repair techs moan about puttin it in. It may not be cost effective for you to have the dealer do it for you, but i'd highly recomment just that.
I have the F350 7.3 dually and I also had the same problem with my passenger side door lock. I had it at the dealer for some maint. and ask them the cost to fix the door lock for me it was 350 bucks, I was in shock, so I told them not to do it and I would do it myself. I walk over to the parts department to get the new accuator (motor) and was expecting it to cost a small fortune but to my surprise it was only 30 bucks. I went home and it only took me about 15 min to change it out. first thing you have to do is take of the door panel which is very easy. first remove a small black cover in the upper left hand side it just pops off. secound pop of the window and lock button panel it removes from right to left just pops up. third there is only 2 screws holding the door panel on one is under the window and lock panel you just removed and the other is behind the door light at the bottom right hand side pop the light cover off self explainatory when you look at it using a screw driver that's where you will find the other screw remove both screws. then lift up on the whole panel it will only come off by lifting striaght up should come off easily. then peel the door cover paper back so you can get to the access hole remove the screws holding the motor on remove the wiring connection you have to unclip the locking bars they just clip in and out. paying attention which one goes where so you can replace then in the same order. pull the motor out and replace it with the new. put everything back together in the same order as you took it apart. it sounds like alot when written down but I found it very simple and saved a ton of money. hope this helps.