Creating a first draft is getting the story on the page. It requires the author to determine the POV (Point of View = who's eyes the reader is seeing the story through), and who the main character is going to be, among other things.
When I started Saving the Land, my main character was an eighteen-year-old boy, Jay Johnson, and the story was written in third person. In third person we are viewing the story through an invisible narrator's eyes. It is written this way:
Jay stepped up into the bus, shaking the bus driver’s hand. "Hi, Mr. Peters."
Then I switched the main character to an eighteen-year-old girl and changed the POV to first person. First person is written as if you're in the character's head - like this:
I stepped up into the school bus and reached to shake the bus drivers hand. He'd always insisted that we start the day by politely greeting each other. "Hello, Mr. Peters."
After writing 30,000 words, I decided to make Jay older, so I started over, again. An additional ten years of life experience added a richness and complexity to the story line it had been missing before.
The first draft phase is when the author answers questions like: When does the main character learn she has a problem? What makes her decide she must deal with the problem and stop ignoring it? What does she learn as she moves through the story? When does she decide to fight back? ...