I didn't come to it easily myself, and I would have thought my degree would have taught me something, but somehow they gloss over a lot of things in business school.

These days there's a lot more online that you can google. Here's the rough areas of coverage I'd go for:

- Corporate fundamentals. What is limited liability? How do I make a co in my country? What are the different types of co available? (GmbH vs AG, LLP vs Ltd, C-Corp vs S-Corp, Charities?)

- What are the financial and taxation setups? Basically, how are entities related to each other? Can I borrow money from my co? How are dividends treated. This is a thing you want an accountant to tell you, because they know the praxis, not just the headline rules of your jurisdiction.

- Finance. What does capital structure mean? What's the difference between equity and debt? What's the difference between your mortgage and your credit card? What are options and warrants? (I spent years trading vol, still there are differences between listed options and employee ones, esp wrt tax). What do junior and senior mean? What are preferred shares, and what are convertible bonds? Since we're talking here, HN people have written a load of articles about SAFE notes and similar. They are quite good about also explaining what your interest is in these situations, because it's often not obvious to a newbie.

Interesting article from a couple of days ago was about Toptal. Those kinds of articles should be read.