Take an introduction to accounting course (https://www.coursera.org/learn/wharton-accounting https://www.coursera.org/learn/wharton-accounting is very good, and

Take an introduction to accounting course (https://www.coursera.org/learn/wharton-accounting https://www.coursera.org/learn/wharton-accounting is very good, and it's free to audit), and you should be able to understand the meaty part of S-1 (and 10-Q/10-K)