I have a 2016 228D. Yours should be "A/C Ready" meaning there is electrical for it at the bottom (read a 30amp circuit breaker) but you will have to drill the hole on the sidewall of the roof for the upper connection (install the water resistant cover) and route a power wire to where it sits on the ceiling. I believe the bottom opening with cover is present but there is no wire in it, you have to add that. Then of course cut the holes in the roof where it sits, there should be a "framed" opening already there the center of which is denoted by a "button" thing on the inside ceiling to help you get started.
There are some GREAT videos out there on doing this with some great tips I wouldn't have necessarily come up with out of the gate such as putting a large box on the inside under where you cut the roof so the debris falls in it.
Also, DO NOT put any weight on the roof. You can't climb up there or you will break it. That part is what can make this the most difficult. I have seen people talk about using at least 2 ladders with ceiling joists spanned across them to take any weight while you work on top.
I have the Coleman Mach 15 which does great in the Texas Heat. I do not have/use those solar covers over the bunk ends but we do not spend an enormous amount of time in the camper either during the day as we are usually site seeing.
One of the videos I watched: