Microsoft has a guide to developing basic Metro style apps (JavaScript)  here
see http://msdn.microsoft.com/en-us/library/windows/apps/br229565.aspx

but unfortuntely itit's all in pieces with a sidebar , so here it is one sequence. Even though it's a skeleton, it does give you a roadmap to research the stuff that it's supposed to point to.

This documentation is preliminary and is subject to change.]

This section walks you through the steps to create a complete but basic Metro style app using JavaScript. Metro style apps are focused, fluid, and elegant. From the new Start screen to new UI layout and controls, the presentation of your app is about showing off what it's great at.

1. Creating a UILearn how to create a user interface for your app.
   In this section, you can learn how to choose the right UI surfaces for your Metro style app, how to layout your app, how to add controls and content for you app's UI. You can also learn how to create live tiles, the face of your app on the Start screen.
   You can use JavaScript with HTML and CSS to create a great app with the Metro style UI. Metro style app are full screen and they immerse your users in the experience you create for them. App chrome is on-demand, so there is nothing to distract a user from the things they want to do in your app  
2. Responding to user inputThis section shows you how to identify the input devices that are connected to your customer's system, how to respond to touch, keyboard, mouse, and ink input. This way, your app can be as at home on a small slate device as it can on a full size desktop with external monitor, keyboard, and mouse.  .
3. Accessing files and dataLearn how to read, write, and save to files, as well as how to manipulate XML data.
   In this section, you can learn how to read, write, and save files, as well as how to add picker controls so users can open and save their files.
   In this section
   

   Topic	Description
   Accessing data from files	Learn to read and write files and to present files to users.
   Adding file picker controls	Learn how to add file picker controls so users can easily open and save their files using a familiar UI.
   Copying and pasting data	Learn how to use the clipboard to copy and paste data between controls or apps.
   Encrypting data and working with certificates	Learn how to encode and decode data, how to encrypt and decrypt data, and how to work with certificates.
   Using XML in your app	Learn how to work with XML in your app, including reading and writing XML content, traversing a DOM tree, and using XPath and XSL transformations. Quickstart: Working with files Learn to create, write, and read files from the file-system. How to get lists of files and folders from a folder Get a list of the files and folders in a folder, library, device, or network location. How to get sorted lists of files Get lists of files based on criteria that you specify. Related topics Windows.Storage namespace Windows.Storage.Search namespace Windows.Storage.Streams namespace

4. Using async programming patterns (yup, that's pretty much  empty)Asynchronous programming can help you keep your apps responsive.
   Asynchronous programming is designed for use by all Metro style app developers.
5. Managing the application lifecycleLearn how to launch, suspend, and resume your app while keeping app data safe and fresh.
   

   How to activate an app	Shows how to define the activation experience for your app.
   How to suspend an app	Shows how to save important application data when the system suspends your app.
   How to resume an app	Shows how to refresh displayed content when the system resumes your app.
   Guidelines for managing app lifecycle	These guidelines can help you design the suspend and resume behavior of your app.
   Managing application data	Shows how to use the application data API to accomplish key tasks.

6. Defining application resourcesLearn how to define your app's resources to improve maintainability and localization.
   

   Quickstart: Managing user- and device-specific UI resources	This quickstart walks you through the steps required to manage user- and device-specific UI resources for a Metro style app.
   Quickstart: Loading user- and device-specific UI resources	This quickstart walks you through the steps required to load user- and device-specific UI resources for an app.
   How to manage string resources	This topic explains how you can create and manage string resources for your Metro style app.
   Guidelines and checklist for app resources	This topic describes best practices for using app resources in a Metro style app.

7. Packaging your appLearn how to use Visual Studio to create an app manifest and package your app.
   
   There are several steps to packaging an app in preparation for publishing it to the Windows Store:
   1. Install Visual Studio
   2. Create the app
   3. Debug the app
   4. Validate a local package
   5. These steps and others are described in the tutorial Tutorial: Creating, testing, and publishing your app (1 of 2). For more information, see How to: Install, validate, and upload your package.
8. Debugging and testing appsLearn how to use tools to debug and test your app
   

   Running Metro style apps from Visual Studio	Running Metro style apps from Visual Studio shows you how to run your app on a local machine, in the Metro style app simulator, or on a remote device.
   Debugging Metro style apps	Debugging Metro style apps introduces the Visual Studio debugger that can help you find and fix bugs in your code.
   Analyzing the code quality of Metro style apps with Visual Studio code analysis	Analyzing the code quality of Metro style apps with Visual Studio code analysis shows you how to find some common problems that are difficult to detect in debugging and testing.
   Creating and running unit tests on a Metro style app	Creating and running unit tests on a Metro style app

   For more information about debugging, see Debugging in Visual Studio in the MSDN Library..

Creating a UI

In this section, you can learn how to choose the right UI surfaces for your Metro style app, how to layout your app, how to add controls and content for you app's UI. You can also learn how to create live tiles, the face of your app on the Start screen.
You can use JavaScript with HTML and CSS to create a great app with the Metro style UI. Metro style app are full screen and they immerse your users in the experience you create for them. App chrome is on-demand, so there is nothing to distract a user from the things they want to do in your app.

This section shows you how to identify the input devices that are connected to your customer's system, how to respond to touch, keyboard, mouse, and ink input. This way, your app can be as at home on a small slate device as it can on a full size desktop with external monitor, keyboard, and mouse.