50 years ago the Japanese had a 3 wheel pickup truck with a hand started diesel engine in the rear.There was a small stove on the cylinder head where a few oily rags were burned to heat it up. I was never close enough to one when starting to know how it was cranked but the driver was at the rear. I believe Subaru made the trucks.
The only instructions for hand starting a diesel engine of any significant size I have run across was for Yanmar marine engines. Those engines seem to have everything engineered in to enable hand starting but it doesn’t sound easy. With an external adjustment on injection timing and individual cylinder decompression valves there’s hope.But while a 20 horsepower engine will move a 40 foot sailboat at a reasonable speed it’s not much for cruising in a sedan on the Autobahn or I-95.