Anyone who thinks a Diesel has a choke knows nothing about Diesels(except the old IH gas start engines)! You can pump the accelerator pedal all day and you won't flood the engine. All the accelerator does is change the rack in the injection pump. "Depress the accelerator 3 times": does this mean a Diesel has a carburetor with an accelerator pump?
Ben300SD: If you don't know what you are writing about, don't give bad advice or better yet give no advice. Did you ever have a manual glow plug MB? I had 6 of them for over 300,000 miles. I still have a 220D and 240D. I know what I'm writing about.
Sheila: Ignore everything Ben300SD says except the welcome and follow Aaron's advice. If it still won't start, keep glowing the plugs longer until the indicator is really red hot and try the starter again. As soon as the engine fires, press the throttle and rev up the engine reasonably and if the engine is in good shape it will run OK. When the engine warms up you can turn the idle knob back so the engine idles correctly.
One note to Aaron: the idle knob only holds the throttle linkage open slightly, it doesn't "enrich anything".
P E H