How to Win8 or WinRT App for CRM

Hi I am new to CRM. I want to develop Win8 App in C# for CRM. I need help.

Please guide me and provide me some sample app to learn from.

1) What SDK, component or Api I need for my Win8 App to do these  operations: Add, update, delete for the tables

2) What webservice to use and How to create Webservice for CRM.

3) What controls or control toolkits available for Win8 App for CRM

4) I see some app in windows 8 appstore:

a) What controls are used in this Mobile CRM or are these specific- controls  used for CRM :

http://apps.microsoft.com/windows/en-US/app/mobile-crm/f5701def-b79c-4133-af37-ff51a050bad9

b) Is this win8 App from resco.net using controls in VS2010 express for Win8

http://www.resco.net/mobilecrm/app.aspx

Thanks