You would certainly have to include the part about how his arm is withered. I think you should also put in the part about Bob Ewell not calling for a doctor. If it were me, I would also focus on why he got charged in the first place. I would write about Bob Ewell being abusive and keeping his kids from having any decent friends. This is presumably why Mayella tried to get Tom Robinson to kiss her.
As to the "how," I would certainly put major emphasis on Atticus Finch. I would play up how he was willing to fight for Robinson even though most people in the community did not want him to.