What is an instance?

Answer 1

A building in the street is an instance of the blueprint. An object in your running code is an instance of the class. When you instantiate a class, it means you are building an object according the class you named. Animal dog = new Animal means variable dog now exists, because you ordered a new instance of animal.

Answer 2

What's a lesson in Sololearn?
If you looked at one you will know