Trying to understand ESOPs

I wanted to know how exactly does it work? I myself never worked in a startup, though curious. Pardon if the question is not hitting the point.

Simply put - They give a piece of paper that shows that you can own X amount over 4yrs and that X amount can actually appreciate in value. But there are lot of conditions - 1. What the exercise value is of the ESOP 2. How easily can you get the money on your stock options 3. How much time you get to sell off your ESOPs 4. Taxation 5. How much percentage of the ESOPs do you get every year 6. How much will the company progress? Etc etc so on and so forth. If you want to know more, there are enough videos like that of Ankur Warikoo you can check on YT. If you have specific questions, I can answer