Essays / I have to do a thesis 4pg. paper on the atomic bomb [4]

Atomic Bomb Paper - Why Was The Bomb Dropped? - How Do I Begin My Essay???

I have to write an essay on why the atomic bomb was dropped. I Have all these books but i dont know where to begin. I know exactly what I want to say I just dont know how to put it in writing. How do i start my thesis statement? How do I Begin my first paragraph? Help??