Need to push the plastic (earlier ones were metal) up and off of the locking rod & door handle rod. Look closely, you will see where they clip over the rods right behind the rods where they make the 90* bend.
The rods will lift or push out of the button & handle mechanism. You can then remove the lock / handle assembly. Usually it's best to tape or tie the two rods up in that area, as they have a tendancy to slip down, and when you're ready to assemble the door panel, you will discover they are out of reach.
Just a suggestion, but while it's open, I put a short piece of foam pipe insulation on each rod to stop rattles.