大家能帮看看公司的stock option 怎么运作的？先谢了

公司给了一些stock option。不知道这个东东怎么运作的，请指教。
签的合同上是这样写的：
1。Enclosed are the assignments of the stock option warrants that will vest 25% at the end of each year for four years from the date of the assignment to you in addition to your agreed compensation provided you remain employed by XXX during the four year term.

Question1 : 这一条是不是说我一定要在公司工作四年，才能拿到股票？从签合同之日起，工作满一年，就走了，是不是25％的股票都没有？

2。 XX has valued the stock at the time of the license at $xxx per share, but the stock is not actively traded and there can be no assurance of its market value now or at any time.

Question2: 这一条是不是说即使工作一年，25%的股票拿到了，也不能公开交易呀？股票已经在纽约股市上市了，只是还数垃圾股一类
3. This warrant assignment shall become exercisable in the amount of 10,000 shares one year after dates provide to you is still employed by XX company.

Question 3: 我是去年8月1号签的这个合同，我已经告诉老板8月份辞职了，那么我感到8月4号，老板是不是也应该给我这10000股股票呢？他会怎么给我这些股票？我还没有股票的帐户呢。我拿了这些股票能不能马上买了呢？或者我根本就拿不到这些股票，因为我只工作到4号，没有满足still employed. 是不是工作到8月低就可以拿到了呢？

谢谢大家了！