Have you noticed that many common phrases we use today are idioms or idiomatic expressions? Count how many you use!
The dictionary defines "idiom" as "a group of words established by usage as having a meaning not deductible from those of the individual words." In short, these phrases shouldn't be taken at face value, so to speak. For example, if you say "a no-brainer,' that doesn't mean someone has no brain. It doesn't translate to a "literal meaning." Rather, this is what's called "figurative language" in literature.
You're always using examples of figurative language in daily speech but you may not know it. The most common type is simile, wherein you compare two things. If you say "My boss is as slow as a turtle in approving my leaves," that's simile. You're getting the qualities or characteristics of a turtle's slowness and comparing that to how your boss makes slow decisions.
Another common type is metaphor, wherein you also do comparisons but it's more of the symbolic kind. For example, when you say "I work better with night owls," that doesn't mean you work in a zoo! Rather, you're using the night owl image to symbolize people who are more productive during the night. If you say, "I'm an early bird," then that means you're using the traits of a bird to symbolize your work ethic or productivity mode.
Other types of figurative language you can discover later on are personification, oxymoron, hyperbole, onomatopoeia and many more. For now, see how much you know of figurative language examples through the common phrases we use every single day. Have fun!