Add comments to Program

Signed-off-by: Marc Duiker <marcduiker@users.noreply.github.com>

tutorials/workflow/csharp/fundamentals/Basic/Program.cs

@@ -3,6 +3,8 @@ using Basic.Activities;
 using Dapr.Workflow;
 
 var builder = WebApplication.CreateBuilder(args);
+// Dapr Workflows and Activities need to be registered in the DI container otherwise
+// the Dapr runtime does not know this application contains workflows and activities.
 builder.Services.AddDaprWorkflow(options =>
 {
     options.RegisterWorkflow<BasicWorkflow>();
@@ -15,6 +17,8 @@ app.MapPost("/start/{input}", async (
     string input,
     DaprWorkflowClient workflowClient) =>
 {
+    /// The DaprWorkflowClient is the API to manage workflows.
+    /// Here it is used to schedule a new workflow instance.
     var instanceId = await workflowClient.ScheduleNewWorkflowAsync(
         name: nameof(BasicWorkflow),
         input: input);