Future Perfect

1. I will have learned to draw by end of next year.
2. You will have known I finished school in last month.
3. I have not sat till you will apologize .

Dear Derek, your examples are not the correct use of future perfect.

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Future Perfect

1. I will have learned to draw (for how long?) by (the) end of next year.
2. You will have known I finished school in last month.

It is incorrect to use future perfect in this sentence. You should say: You know I finished school last month.
3. I have not sat till you will apologize .

It should be: I will not sit till you apologize. It is a conditional sentence, so there is no need to use future perfect.

Future perfect is used when you want to express that something will be done in future (but it's not done now).

Eg. I will have been a father for 2 years by my son's next birthday.

I'm not yet a father for 2 years, but I will be when my son's next birthday comes.