Once the project is created, add the IdentityServer4 package in your authorization server through NuGet:

In the ConfigureServices method of the Startup class, we have to first add the Identity Server by calling the AddIdentityServer method as follows:

    public void ConfigureServices(IServiceCollection services) 
    { 
        services.AddIdentityServer(); 
    }

Next, we will use the Identity Server by calling the UseIdentityServer method in the Configure method in the Startup class as follows:

    public void Configure(IApplicationBuilder app,
      IHostingEnvironment env, ILoggerFactory loggerFactory) 
    { 
        app.UseIdentityServer();
    }