I really need help on how to write a introduction about conflict in macbeth?

ok, so i start with something like.... throughout shakespears play 'macbeth' one of the main themes presented is conflict. but i need to explain what effect this has and how it builds up to a tragic climax at the end and maybe my oppininon but i dont know what to put?! im stressing so much because i have to write an essay on friday in a controlled assesment and i cant even start it! it only needs to be a couple of lines ... please help me!!