I suggest simply asking questions on lemmygrad.
The point of the book club should also be to help one another understand and learn. You aren’t teaching the others, you should all try to engage with the text and each others understanding.
Lastly, the more you read the better your comprehension will be. Consider if audiobooks or different formats might also help you understand better.
Realize that China has not been increasing it’s military spending relative to GDP.
https://data.worldbank.org/indicator/MS.MIL.XPND.GD.ZS?locations=CN-US&start=1989
China does not have an expansive or aggressive posture. The US has about twice the spending as a share of GDP, with a larger nominal GDP. There is nuance to this, but China is absolutely not disproportionately or aggressively building up it’s military.