Good idea to apply lube, I prefer gel lube (or a grease) as opposed to wd40 which doesn't last as long, the mechanism on the back of the exterior handle. If you keep that working smoothly, you shouldn't have to worry about it breaking/working itself out.

Once you get the inner door panel off, you'll be able to figure it out. Be careful with the pastic inside, pull it back gently enough and you can put it back (sometimes even without apply new sealant). I ripped mine the first time I had to do it.