Hi. I am new to Salesforce.I am doing a tutorial, but when I finish a section the "verify Step" button is always disabled. How do I enable it?

Hi. I am new to Salesforce.I am doing a tutorial, but when I finish a section the "verify Step" button is always disabled. How do I enable it?

Hi, I built a simple asp .net application using MVC and tried to use Canvas to integrate to Force.com. But when I debugged in my application, the signed_request always returned null and the Request.HttpMethod was "GET" where I was expecting "POST". Can someone please help me?

Here is my code in my HomeController Index() method:

 string signedRequest = Request.Params["signed_request"];