Implements vs extends: When to use? What's the difference?

Question

Please explain in an easy to understand language or a link to some article.

Answer 1

Extends : This is used to get attributes of a parent class into base class and may contain already defined methods that can be overridden in the child class.

Implements : This is used to implement an interface (parent class with functions signatures only but not their definitions) by defining it in the child class.

There is one special condition: "What if I want a new Interface to be the child of an existing interface?". In the above condition, the child interface extends the parent interface.