To continue where Levi left off 'meaning' is what the movie is all about. The message it is giving to the audience. "To get a big head" means to have a large opinion about yourself. To be very vain, to have a big ego. To be very pleased with yourself.

its confusing there for it doesnt make any "sense" to you. Point and use can be tricky at times. "there is no point/use in trying" in this sentence the meaning is there is no reason to try and doesnt change regardless of the which one you use. If youre still confused i can elaborate more