Easy to do.
Drill out the rivet holding the window to the frame and lift away from the frame.
That's all there is to it.
If you need to replace the glass, the seal and new rivet are available from
www.wolfsburgwest.com. If you need glass, I've got some laying around, which could be had for cheap + shipping.
As far as installing the new glass and seal in the window frame, I'd recommend an auto glass shop. Without the proper tools and skill, you'll end up breaking the glass, tearing the seal, and/or both. (ask me how I know

)