Timing issues, Bosch magneto/ laurel cylinder head

[RalphM]

My friend has this setup;
1916 engine, type A laurel head(Roof), Rebuult Bosch magneto about 1918. Plugs will spark with magneto, there’s gas in the Miller type H carburetor(looked rebuilt), but cannot get the engine to pop off. Adjusted magneto several times still nothing. Long reach modern spark plugs.
Pulled around the yard while making adjustments, still will not fire.
Is there a basic setup procedure for the magneto to get it close?
I’m a V8 Flathead guy, so this is all Greek to me.