What Happens to New Objects in JavaScript?

This question might seem a bit silly to forum users who have been using JavaScript for awhile, but I’ve just recently realized that there’s a gap in my understanding when it comes to Object-Oriented Programming in the language.

When reading up on OOP in JavaScript, I’ve noticed that the language used for the constructor/prototype/new object relationship is one of “storage” and “memory.” However, to my understanding, there’s no way to save new data to a JavaScript file while it’s executing, and due to all code being self-sufficient, all data input into any JavaScript code has to be evenly output.

In short, my question is this: what are “new” objects in JavaScript used for? Are they used to store data and information in a way that I currently not aware of? Barring that, in what situations are they used?

Thank you very much for your time.