Not sure where the question mark goes in you subject line. Although a two speed option was offered for the Model D, they are not common. I ride both a C and a TS, neither with clutch.
On the C, you pedal a bit with the exhaust valves lifted, then drop them and (if the gods are with you), away you go at essentially full speed. It is not a very flexible engine so it works best at one speed, largely determined by the inlet valve spring tension.
On the TS, you attain forward motion (trot along side or paddle while straddled) with the exhaust valves lifted and in first gear, then drop the lifters and away you go at low speed, when ready to shift, use the exhaust lifter to remove stress on the system and go into high gear.
If by poor planning, you find yourself in neutral with the bike at a stop, Kill the engine and start over.
Try it on your '13 by ignoring the clutch. Then you will get an idea of how these things behave in dense traffic or uphill starts and you will praise the inventor of the clutch.