For the doors, start by removing the access panel on the interior surface of the door which is held in place with a number of sheet metal screws. Yours May or May not have a vinyl cover over it. If it does, that would obviously need to be carefully removed to access the screws. With the access panel out of the way, you can see the guts of the dl assembly when you focus a beam of light up in there. There is a thin metal lock plate adjacent to the lock cylinder that can be worked out initially with a screw driver and then pulled out enough with pliars to free the dl cylinder for removal. This lock plate is accessed from outside the door. Reverse the process for installation of the replacement cylinder.
I've never messed with the t-handle cylinder other than to remove the whole handle assembly as a unit from the liftglass which is pretty self-explanatory.