minor updates to the .NET docs (#5552)

## Why are these changes needed?

<!-- Please give a short summary of the change and the problem this
solves. -->

## Related issue number

docs/dotnet/core/index.md

@@ -7,11 +7,15 @@ Any important differences between the language versions are documented in the [D
 ## Getting Started
 
 You can obtain the SDK as a nuget package or by cloning the repository. The SDK is available on [NuGet](https://www.nuget.org/packages/Microsoft.AutoGen).
+Minimally you will need the following:
 
 ```bash
+dotnet add package Microsoft.AutoGen.Contracts
 dotnet add package Microsoft.AutoGen.Core
 ```
 
+See [Installation](./installation.md) for more detailed notes on installing all the related packages. 
+
 You can quickly get started by looking at the samples in the [samples](https://github.com/microsoft/autogen/tree/main/dotnet/samples) directory of the repository.
 
 ### Creating an Agent
@@ -74,7 +78,7 @@ dotnet add package Microsoft.AutoGen.AgentHost
 You can run the backend on its own:
 
 ```bash
-dotnet run --project Microsoft.AutoGen.RuntimeGateway
+dotnet run --project Microsoft.AutoGen.AgentHost
 ```
 
 or you can run iclude it inside your own application:
@@ -117,6 +121,8 @@ Console.WriteLine("Backend URL: " + url);
 await app.WaitForShutdownAsync();
 ```
 
+You can find more examples of how to use Aspire and XLang agents in the [Microsoft.AutoGen.Integration.Tests.AppHost](https://github.com/microsoft/autogen/blob/acd7e864300e24a3ee67a89a916436e8894bb143/dotnet/test/Microsoft.AutoGen.Integration.Tests.AppHosts/) directory. 
+
 ### Configuring Logging
 
 The SDK uses the Microsoft.Extensions.Logging framework for logging. Here is an example appsettings.json file with some useful defaults: