Doctors often don't know nearly as much as we like to think they do. And scientific journals tend to be aimed towards people who've already been taught some fundamentals and focusing more on scientifically coming to better understand still unknown phenomenon rather than existing well understood theories.
Wikipedia is a good source despite what people say about it. As is anything that teaches basics in biochemistry.
I can tell you (you can Google this to find more authoritive sources) my understanding of how these drugs work.
I'll start with spironolactone.
As I understand it, spironolactone is currently most suspected to be metabolized by your liver into other related compounds which in turn act biologically by binding to molecular receptor sites, among the receptor sites being androgen sensitive receptors. In androgen receptors, it acts as an antagonist. It binds to them but does not trigger a biological reaction, thereby competitively blocking those sites from androgen receptor agonists like testosterone. It has effects on some other receptor sites too resulting in some of its other pharmacological uses and potential side effects. Such as by also antagonizing mineralocorticoid receptors resulting in some of its effects as a potassium sparing diuretic.
Estradiol by comparison is relatively simple to explain. It works in you the same way it works in any normal human. As the primary human estrogen, most analogous to testosterone in males, it functions as an estrogen receptor agonist. Triggering effects of biological feminisation.
Of course there's a lot more to know than just that, such as how those receptors interact with other functions of bodily processes, the role of genes and proteins, etc. But that's the general basics of it.
Hope you find the information you're looking for and hope any of this helped.
Keep in mind, male and female bodies are largely the same once you take out hormonal sex differentiating influences. There's some differences due to genetics, but they aren't enormously relevant in terms of how estrogens work on human cells.
