.Net: Add missing code samples reference to dotnet Readme (#6408)

### Motivation and Context

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### Contribution Checklist

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- [ ] The code builds clean without any errors or warnings
- [ ] The PR follows the [SK Contribution
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---------

Co-authored-by: Mark Wallace <127216156+markwallace-microsoft@users.noreply.github.com>

dotnet/README.md

@@ -4,8 +4,9 @@
 
 To run the LLM prompts and semantic functions in the examples below, make sure
 you have an
-[OpenAI API Key](https://platform.openai.com) or
-[Azure OpenAI Service Key](https://learn.microsoft.com/azure/cognitive-services/openai/quickstart?pivots=rest-api).
+
+- [Azure OpenAI Service Key](https://learn.microsoft.com/azure/cognitive-services/openai/quickstart?pivots=rest-api) or
+- [OpenAI API Key](https://platform.openai.com).
 
 ## Nuget package
 
@@ -82,6 +83,18 @@ requirements and setup instructions.
 9. [Chatting with ChatGPT and Images](./notebooks/08-chatGPT-with-DALL-E-3.ipynb)
 10. [BingSearch using Kernel](./notebooks/10-BingSearch-using-kernel.ipynb)
 
+# Semantic Kernel Samples
+
+The repository also contains the following code samples:
+
+| Type                                                                       | Description                                                                                                            |
+| -------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------- |
+| [`GettingStarted`](./samples/GettingStarted/README.md)                     | Take this step by step tutorial to get started with the Semantic Kernel and get introduced to the key concepts.        |
+| [`GettingStartedWithAgents`](./samples/GettingStartedWithAgents/README.md) | Take this step by step tutorial to get started with the Semantic Kernel Agents and get introduced to the key concepts. |
+| [`Concepts`](./samples/Concepts/README.md)                                 | This section contains focussed samples which illustrate all of the concepts included in the Semantic Kernel.           |
+| [`Demos`](./samples/Demos/README.md)                                       | Look here to find a sample which demonstrates how to use many of Semantic Kernel features.                              |
+| [`LearnResources`](./samples/LearnResources/README.md)                     | Code snippets that are related to online documentation sources like Microsoft Learn, DevBlogs and others               |
+
 # Nuget packages
 
 Semantic Kernel provides a set of nuget packages to allow extending the core with