Why did I get one undefined in the getItem command and two undefined in the console.log command?

Uncaught TypeError: Failed to execute ‘setItem’ on ‘Storage’: 2 arguments required, but only 1 present.
at :1:14

localStorage.setItem{"first_example"} = 1;
Uncaught SyntaxError: Unexpected token ‘{’
  
The setItem() method of the Storage
  interface, when passed a key name and value, will add that key to the given
  Storage object, or update that key's value if it already exists.
Which is what you’re looking for?  I don’t get the output from the undefined.  You can’t output a set.
Setters add/update a value
Getters return a value.
Which is what you’re looking for? I don’t get the output from the undefined. You can’t output a set.
Setters add/update a value
Getters return a value.
I know, I meant that getting the following output from the getter:
Is what I was looking for 
I just meant to show the entire process from start to finish (including the undefined console output for the setter), was fine