What else do you study in vocational school?

That depends on what major you choose. Most vocational schools learn mathematics, Chinese, foreign languages, and then simple law besides specialized courses. Of course, textbooks are different from those in high school!

If you didn't sign up before leaving your job, I suggest you don't go to vocational schools, because vocational schools are somewhat fraudulent and you can't learn anything in vocational schools. The only thing you can learn is love and bad habits!

This is just my opinion and suggestion.

Take your time!