Nicely written introduction to OOP. I noticed you made a mistake in an example, the method is outside the object.

let user = {
  firstName: "Jane",
  lastName: "Doe",

//method
    getFunction : function(){
        return (`The name of the person is 
          ${person.firstName} ${person.lastName}`)

}

console.log(user.getFunction());// The name of the person is Jane Doe