A probably really stupid question for a wannabe author but...

Okay, so I am really lost. What is it called or how do I look for examples of when people use other things to describe something else?? Like when someone is angry, a common one would be "when they see red" or "a bull in a china shop." Or other I can think of atm being "her laugh was like a pixie bell..." to describe a delicate/light laugh. What are these called? I have Autism and descriptive examples like these are difficult for me so sometimes I like to try and find examples to help, but I never know what to search for. I end up with the strangest search history.