What is the difference between the concepts in C#: class, object, instance?

Question

OOP

Started learning c#.
In php, everything was clear: a class is a template, and objects are concrete instances of a class. Those. object and instance there denoted the same thing.
In #, as I understand it, the concepts of an object and an instance are distinguished. The question is, what are the differences? How is it in the official documentation and Richter?

Answer 1

An object is an instance of a class.
A class is a description of an object

Answer 2

In php, these concepts are also different.

Answer 3

https://www.youtube.com/watch?v=x0udrpe_gZE&t=6s