IdentityServer4.Quickstart.UI | Starter UI for in-memory IdentityServer4

I created an empty asp.net core web app that has identityserver4 set up in the program. For some reason when I run the program the browser looks like this

instead of how it should look like

The program was not running on .net 6.0 because it was saying could not find the /index but I downloaded the templates of IdentityServer4 by running the cmds dotnet new -i identityserver4.templates and dotnet newis4ui which gave me the UI which includes the /index. See this github for identityserver UI. So I then switched it from .net 6.0 to .net 5.0 in the project property settings which worked but displayed this weird format.

startup.cs

I created an empty asp.net core web application (dotnet new web -n ) and went to the github for IdentityServer4.Quickstart.UI and was followed the instructions to add the quickstart UI. I first did the powershell cmd iex ((New-Object System.Net.WebClient).DownloadString('https://raw.githubusercontent.com/IdentityServer/IdentityServer4.Quickstart.UI/main/getmain.ps1')) to download the files and run the application but it keeps telling me Index not found but the file is inside of the Views folder. So I then deleted all those files it downloaded from the project and installed it using its templates by running the cmds dotnet new -i identityserver4.templates then dotnet new is4ui --force which downloaded those files again onto my project. However, it keeps telling me the same message.

I noticed that under the Quickstart folder, contains a folder named Home which has the HomeController.cs and the namespace is as IdentityServerHost.Quickstart.UI... do I need to change that namespace to match my solution i.e. ids.Quickstart.Home?

What is causing this to display that error when infact there is the Index.cshtml file inside of the Views folder?**

This is my startup.cs file:

I am using IdentityServer 4 with an Angular 10 client that uses OIDC Client JS:

To redirect a user for signin I am calling signinRedirect on the Angular's client:

I'm implementing Identity Server 4 in an MVC Core app. I have Azure Active Directory as an external provider and all this is so far working fine. I've also implemented the QuickStart UI (as per https://github.com/IdentityServer/IdentityServer4.Quickstart.UI#quickstart-ui-for-identityserver4)

I want to add a step in this process, before redirecting back to the client, where a user interface presents a list of options to select from, with the result of this being added as a claim that is then available in the client. The way I see this is by deferring the Redirect that occurs at line 143 in the ExternalController (https://github.com/IdentityServer/IdentityServer4.Quickstart.UI/blob/main/Quickstart/Account/ExternalController.cs)

I have tried redirecting to a custom action and taking user input, like below:

I am trying to implement IdentityServer4 in .Net core 3.1

I get below message in debug window:

In Identity Server 4, Quick Start, ExternalController.cs - CallBack method, I found the following: