imho such "level" indications help little. people will look at the cookbook entries for the things they want to do, regardless of level. what i do think is extremly useful is the rest of this intro telling what we do and which bundles we are going to use. that is helping me decide if i care about the tutorial.

if anything schematic, i would propose to formalize this, having a sort of heading table saying with sections Goals, Bundles Used, Prerequisites. the prerequisites would tell which book chapters you are supposed to already know in order to do this, so that we do not have to repeat how odm annotations work all the time and such things.