The cab comes off as a separate piece. First you must remove the entire cab from the body, and flip it over. You will notice a tan molding inside the bottom of the cab representing the cab interior (seats and control panel), and you must pull this piece out. Once you have this tan piece out, you will notice a clear plastic molding for the windows. PLEASE BE AWARE that the front windows and side windows are a part of one single piece, and too much pressure on any part of the piece might crack the plastic.Take a small flathead screwdriver, pry it underneath the clear plastic window on the side wall of the cab, and it should come loose. Repeat for the other side. Once you have both clear plastic sides loose, gently coerce the piece out being careful not to break the clear plastic. Gently pull the piece out, with attention to now pulling the front windows out. The entire clear plastic should have lifted out.
For the front portal window, you will notice upon inspection of the interior of the cab piece that the "nose" of the engine is a separate piece and separates from the cab. On the front side walls of the cab interior are two tabs, one on each side. Use a small flathead screwdriver to disconnect these tabs, and the nose of the engine should pry loose. Simply remove the clear plastic molding and put in a safe place.
Also notice that the silver headlight housing (both front and rear) comes out along with the light tube, so there is no need to mask it or paint it silver later on. Store all these small pieces in a safe place... I use a ziplock bag.
Let me know if you have any additional questions. I painted 3 of these 80s in NYC lightning stripe, and two Kato 90s in the same livery. What roadname are you gonna paint yours?