Please explain, what does the following poem mean?

A man's fate depends on himself. What is in life is yours, and what is not in life cannot be forced. Many things are our own lives, and we can't blame others. When luck comes, you will get what you want, and vice versa. Three points are destiny takes a hand, and seven points are on your own.

The general feeling is that you should seize your little chance.

My friends, although some things have to rely on a little luck, success is hard after all.

Please forgive me if there is any language error! !