The classroom portion is very important, probably the most important part of the whole class. But it is necessarily not as in depth as a book dedicated to how to survive on the streets. The classroom portion would consist of watching a video that tried to emphasize some point and then as a group we would discuss it. The idea is to get you thinking about certain scenarios and not just present you with an answer. In real life there is frequently no one right answer, there are pros and cons to each decision you make. You can download the BRC booklet and see what it talks about in there (the videos just back it up). Off the top of my head it covers SEE (Search, Evaluate, Execute), pre-ride safety checks, lane positions, ladder of risk and probably many other topics.
I found the classroom portion boring as I read everything before hand so I wasn’t having to think for myself. That may have put me at a disadvantage, I’m not sure, but either way I cannot recommend strongly enough Proficient Motorcycling. It really highlights all the potential pitfalls out there that can catch you out and ways to mitigate the risk. Kind of freaked me out at the beginning to be honest.