I’ll second that, it’d be well worthwhile learning the nine classes, plus the subdivisions, and the associated placards. That’s about 20% of the course material right there. Plenty of places on line to find this.
But don’t sweat it, a decent instructor can get total noobs through their exams first time without any prior reading, though I disagree that the course is idiot-proof: as Douglas Adams wrote in Mostly Harmless, “a common mistake that people make when trying to design something completely fool-proof is to underestimate the ingenuity of complete fools” 