Literary devices in the story of my life by Helen Keller please?

Look up literary devices then read the book.

Anything can be called a literary device, and some might be very subtle. A figure of speech could be called a literary device, and just a brief look at the bible finds over 900 kinds of figures of speech, some with dozens of variations. If you say one thing is like another, "You are like a dog," that is a simile. If you say one thing is another, "You are a dog," that is a metaphor. If you call one thing by the name of another, "Dog!", that is hypocatastasis.

A figure of speech may be the same or different from a rhetorical device, which may be the same or different from a literary device. Here are some rhetorical devices:
mentalfloss.com/article/60234/21-rhetorical-devices-explained

A literary device might be a change in the typeface used to print something. Boldface type and italic type are the most common examples. A chapter heading is a literary device that alerts you to the general subject or some important point to watch for. I have seen one book where a sentence was divided between two chapters to emphasize how shocking it was.

Read the book. You might notice something that nobody else did. And that is just what the author wanted to happen.