the reactions are pretty straightforward. aminoacetaldehyde diethyl acetal (or, 2,2-diethoxyethylamine, if you like) is turned into the formamide with propyl formate (why propyl formate? the reaction is carried out at reflux, suppose propyl formate boils at a high enough temperature to make the reaction work)
then the formamide is dehydrated to the isocyanide with the reagent you get from reacting carbon tetrachloride and triphenylphosphine. that's a trick a few uses (see the "Appel reaction")