Blazor SignalR tutorial for .NET 8 (#29681)

Author: guardrex

aspnetcore/blazor/tooling.md

@@ -475,7 +475,7 @@ To create a Blazor app on macOS, use the following guidance:
   > [!NOTE]
   > Visual Studio for Mac will be able to create Blazor Web Apps in an upcoming release.
 
-<!-- HOLD FOR 8.0 UPDATE TO USE VS UI
+<!-- UPDATE FOR 8.0
 
 In the sidebar, select **Web and Console** > **App**.
 
@@ -599,7 +599,7 @@ For more information on template options, see the following resources:
 
 :::moniker range=">= aspnetcore-8.0"
 
-<!-- HOLD FOR 8.0
+<!-- UPDATE FOR 8.0
 
 * [`blazor`](/dotnet/core/tools/dotnet-new-sdk-templates#blazor)
 

aspnetcore/blazor/tutorials/build-a-blazor-app.md

@@ -33,8 +33,18 @@ At the end of this tutorial, you'll have a working todo list app.
 
 ## Prerequisites
 
+:::moniker range=">= aspnetcore-8.0"
+
+[Download and install the .NET 8.0 Preview](https://dotnet.microsoft.com/download/dotnet/8.0)
+
+:::moniker-end
+
+:::moniker range="< aspnetcore-8.0"
+
 [Download and install .NET](https://dotnet.microsoft.com/download/dotnet) if it isn't already installed on the system or if the system doesn't have the latest version installed.
 
+:::moniker-end
+
 ## Create a Blazor app
 
 :::moniker range=">= aspnetcore-8.0"