Cannot add blocks to the custom page type

So I have created a page type and I am using this code for that

 [ContentType(DisplayName = "Dashboard Page", GUID = "84e59e7c-0dac-4574-b87e-6c3c141e405c", Description = "Dashboard of custom logged in users")]
    public class DashboardPage : StandardPage
    {
    }

The issue I am facing is that I cannot add Block to the pages created under this page type. Am I missing something?