Manage a Child

I do not know why, I told Alan to do homework and he just wants to play. He always says yes or okay to me but at the end, he was doing something else. I do not know how to teach my own child. I do not know how can he get good grades. He just always make me angry. He never listens to me, he never studies hard. I do not know what will happen to him in the future. I am very worry...