The future perfect tense is not commonly used in English. It indicates that an action will be completed in the future (usually before some other action or event).
I will finish my Russian course in June. In July, I will begin studying Chinese.
By the time I begin studying Chinese, I will have finished my Russian course.
When I finish this race, I will have run a total of five miles.
Before they leave for Miami, they will have visited Houston and New Orleans.
The important thing to remember is the time of completion. (Beginning time may vary.)
I started studying last year. I will have passed my exams when I graduate next June.
I am studying right now. I will have passed my exams when I graduate next June.
I will start studying next month. I will have passed my exams when I graduate next June.