The schematic drawing does designate the doors as the pop outs from the door openings. The instructions do not mention the door assembly, but I embellished the doors and installed by gluing hinges to the opening.
I have a video showing what was done for the doors.
https://www.youtube.com/watch?v=fsc_TeoYUVo&list=PLXHh3hA0IAgXFUBmoQTYSW7CNaqK60hW5&index=29