I have been allotted 20,000USD stocks by Coursera

You can sell them from the brokerage account Coursera provides you. Keep in mind that you will be taxed according to US 35.8% , but then , you will be refunded the amount of cash that was excess of your tax slab. You can sell these stocks only on certain specific dates ( trading window) that Coursera will tell you. Mostly ut will be only couple of weeks in a year. At the end of the vesting period you will be left with about ~60% of units due to taxes. This is the major con. The taxes are ridiculous. And on top of it you will have to pay Long-term capital gains tax if you don't sell before 2 years.