Add debug.md file explanation

README.md

@@ -69,6 +69,12 @@ Once the user completes the exercise they will be shown this file, which gives t
 
 See the C# floating-point-numbers exercise's [after.md file](./languages/csharp/concept-exercises/numbers-floating-point/.docs/after.md) for an example.
 
+#### `.docs/debug.md`
+
+This file explains how a user that is coding in the browser can still do "debugging."
+
+See the C# floating-point-numbers exercise's [debug.md file](./languages/csharp/concept-exercises/numbers-floating-point/.docs/debug.md) for an example.
+
 ## Repository structure
 
 Things are grouped into several subdirectories:

languages/csharp/concept-exercises/bitwise-operations/.docs/debug.md

@@ -0,0 +1,10 @@
+# Debug
+
+When a test fails, a message is displayed describing what went wrong and for which input. You can also use the fact that any [console output][programiz.com-basic-input-output] will be shown too. You can write to the console using:
+
+```csharp
+Console.WriteLine("Debug message");
+```
+
+[docs-string]: https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/strings/
+[programiz.com-basic-input-output]: https://www.programiz.com/csharp-programming/basic-input-output

languages/csharp/concept-exercises/dates/.docs/debug.md

@@ -0,0 +1,10 @@
+# Debug
+
+When a test fails, a message is displayed describing what went wrong and for which input. You can also use the fact that any [console output][programiz.com-basic-input-output] will be shown too. You can write to the console using:
+
+```csharp
+Console.WriteLine("Debug message");
+```
+
+[docs-string]: https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/strings/
+[programiz.com-basic-input-output]: https://www.programiz.com/csharp-programming/basic-input-output

languages/csharp/concept-exercises/enums/.docs/debug.md

@@ -0,0 +1,10 @@
+# Debug
+
+When a test fails, a message is displayed describing what went wrong and for which input. You can also use the fact that any [console output][programiz.com-basic-input-output] will be shown too. You can write to the console using:
+
+```csharp
+Console.WriteLine("Debug message");
+```
+
+[docs-string]: https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/strings/
+[programiz.com-basic-input-output]: https://www.programiz.com/csharp-programming/basic-input-output

languages/csharp/concept-exercises/numbers-floating-point/.docs/debug.md

@@ -0,0 +1,10 @@
+# Debug
+
+When a test fails, a message is displayed describing what went wrong and for which input. You can also use the fact that any [console output][programiz.com-basic-input-output] will be shown too. You can write to the console using:
+
+```csharp
+Console.WriteLine("Debug message");
+```
+
+[docs-string]: https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/strings/
+[programiz.com-basic-input-output]: https://www.programiz.com/csharp-programming/basic-input-output

languages/csharp/concept-exercises/numbers/.docs/debug.md

@@ -0,0 +1,10 @@
+# Debug
+
+When a test fails, a message is displayed describing what went wrong and for which input. You can also use the fact that any [console output][programiz.com-basic-input-output] will be shown too. You can write to the console using:
+
+```csharp
+Console.WriteLine("Debug message");
+```
+
+[docs-string]: https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/strings/
+[programiz.com-basic-input-output]: https://www.programiz.com/csharp-programming/basic-input-output

languages/csharp/concept-exercises/strings/.docs/debug.md

@@ -0,0 +1,10 @@
+# Debug
+
+When a test fails, a message is displayed describing what went wrong and for which input. You can also use the fact that any [console output][programiz.com-basic-input-output] will be shown too. You can write to the console using:
+
+```csharp
+Console.WriteLine("Debug message");
+```
+
+[docs-string]: https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/strings/
+[programiz.com-basic-input-output]: https://www.programiz.com/csharp-programming/basic-input-output