Update free-courses-en.md (#8269)

courses/free-courses-en.md

@@ -276,6 +276,7 @@
 * [C# Tutorial - Full Course for Beginners](https://www.youtube.com/watch?v=GhQdlIFylQ8) - Mike Dane (freeCodeCamp)
 * [C# Tutorial For Beginners - Learn C# Basics in 1 Hour](https://www.youtube.com/watch?v=gfkTfcpWqAY) - Moshfegh Hamedani (Programming with Mosh)
 * [Domain-Driven Refactoring - Jimmy Bogard - NDC London 2022](https://www.youtube.com/watch?v=f64tZ90Dntg) - Jimmy Bogard
+* [Fundamentals of Programming: Understanding C#](https://www.udemy.com/course/understandingc/) - Jesse Dietrichson (Udemy)
 * [Learn how to program: C# and .NET](https://www.learnhowtoprogram.com/c-and-net) - Epicodus Inc.