add how to chapter

Readme.md

@@ -41,7 +41,7 @@ echo "<?xml version='1.0' encoding='utf-8'?>
     <value>Hello {0}</value>
     <comment>0 = name</comment>
   </data>
-  <data name='World' type='System.String'>
+  <data name='World'>
     <value>World</value>
   </data>
 </root>
@@ -143,7 +143,7 @@ echo "<?xml version='1.0' encoding='utf-8'?>
     <value>Hallo {0}</value>
     <comment>0 = name</comment>
   </data>
-  <data name='World' type='System.String'>
+  <data name='World'>
     <value>Welt</value>
   </data>
 </root>
@@ -162,6 +162,87 @@ dotnet run
 In the code from `Program.cs` you can see there is explicit rebuild of the format string required after the culture switch.
 The `IResourceString` object themselves are rebuilding the culture specific string.
 
+
+## How it works
+
+The ResourceString.Net source code generator operates by reading all `AdditionalFiles` with the `.resx` file extension and generating a static class based on the specified `data` elements within the file.
+
+For example, given the following XML element:
+
+```xml
+<data name='World'>
+  <value>Welt</value>
+</data>
+```
+
+the source code generator transforms it into the following `C#` class members:
+
+```cs
+#region World 
+
+private static readonly Lazy<IResourceString> LazyWorld = new Lazy<IResourceString>(
+    () => new ResourceManagerString("World", ResourceManager, CultureInfo.CurrentCulture),
+    LazyThreadSafetyMode.PublicationOnly
+);
+
+public static IResourceString World => LazyWorld.Value;
+
+#endregion // World 
+```
+
+If an element contains a format string, such as:
+
+```xml
+<data name='Greetings'>
+  <value>Hello {0} and {1}</value>
+</data>
+```
+
+the generator generates following code to support the formatted string:
+
+```cs
+#region Greetings 
+
+internal static class Greetings 
+{
+  private static readonly Lazy<IResourceString> LazyFormat = new Lazy<IResourceString>(
+    () => new ResourceManagerString("Greetings", ResourceManager, CultureInfo.CurrentCulture),
+    LazyThreadSafetyMode.PublicationOnly
+  );
+
+  public static IResourceString Format => LazyFormat.Value;
+  
+  public static IResourceString From(IResourceString p1, IResourceString p2) => new FormattedResourceString(
+    Format, 
+    p1,
+    p2
+  );
+} 
+
+#endregion // Greetings  
+```
+
+In cases where the element with the format string includes a comment element like:
+
+```xml
+<data name='Greetings'>
+  <value>Hello {0} and {1}</value>
+  <comment>0 = name, 1 = otherName </comment>
+</data>
+```
+
+the source generator extracts the parameter names from the comment instead of using generic names:
+
+```cs
+public static IResourceString From(IResourceString name, IResourceString otherName) => new FormattedResourceString(
+    Format, 
+    name,
+    otherName
+);
+```
+
+This allows for more descriptive parameter names in the generated code.
+
 ## The ResourceString-Classes
 
 ### IResourceString