The harvester is an amazingly complex and multifunctional machine. The blade cuts the stems, then they are captured by the feeder, go inside, where the grains are separated from the stems, and all this happens inside the harvester, while only cleaned grain comes out.
I thought it would be easier to draw the harvester from the front view. So I first drew the cutter and feeder, then added the wheels and the harvester body behind it, and some details.
If you study photos of a harvester, you can see what it has. Some kind of cabin, some kind of ladder to get into the cabin, a grain container on top. If you arrange all this somehow, you get a recognizable image.