There are tons of literary devices in these chapters. I will give you a few examples to get you started. In chapter 12, Jem starts to experience growing pains and Scout is having trouble coping with his treatment of her. Atticus has been called to the state capitol because, as Scout says:
As if that were not enough, the state legislature was called into emergency session and Atticus left us for two weeks. The Governor was eager to scrape a few barnacles off the ship of state; there were sit-down strikes in Birmingham..
"Scraping the barnacles off the ship of state" is a metaphor that means the governor was trying to clean things up.
Calpurnia is getting the children ready for church. She scrubs Scout harder than usual, even peeks in on Jem. Of Scout's dress, Scout says:
She had put so much starch in my dress it came up like a tent when I sat down.
This is a simile. The author is comparing the starched ress to a stiff "tent."
You can find literary devices in almost every paragraph!
In chapter 14, Aunt Alexandra has arrived. The chapter begins with Scout asking Atticus about the meaning of rape. The children reveal they have been to church with Calpurnia. Aunt Alexandra is appalled. Scout sasses her and Atticus becomes angry:
Atticus turned his head and pinned me to the wall with his good eye. His voice was deadly: "First, apologize to your aunt."
Do you think Atticus literally pinned Scout to the wall? No -- this is another literary device. What is it? Do you know? I think you do!
Continue in this way, and you will find other examples.