How to study TR theoretical knowledge

[KayPam]

Hello,

I am currently at the beginning of my TR.
I was a bit surprised to discover there is no groundschool. Everything is computer base training, except for a set of 4 times 2 hours in class, where we can ask questions.

What I do have is ethos CBT and the FCOM. I finished all ethos CBT courses.
I found the FCOM is very painful to read (especially parts like ATA22) but contains much information, whereas the Ethos CBT is quite simplified.

Problem is, when I look at question banks (for example, smart cockpit), I'm finding questions to which the answer was not in the Ethos CBT, and difficult to find in the FCOM, or sometimes not present at all in the FCOM.
Example : "The APU BLEED valve is automatically closed above ______ feet descending by the ECB." : nowhere to be found in the FCOM.
When I look at a question bank obtained inside my ATO, the questions seem more reasonable but still some are difficult without a thorough read of the FCOM.
2400 pages is a big read ! I don't think it possible to learn every detail within only 4-5 weeks to the theoretical test...

So my question is simple, how can I properly and efficiently learn about aircraft systems ?

Thanks

[rudestuff]

By flying it for about 10 years

[Banana Joe]

The way I did it is that I watched/did a CBT system chapter and then I read and studied that system on the FCOM.
That is, Engines and APU CBT and then chapter 7 of the FCOM vol. 2 (B737). For last I did the question bank covering that syatem and reviewed the bits I got wrong.

Not so different from ATPL theory, but much more relevant!
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