"Fortunately, we are providing UX guidelines to developers. Unfortunately, those guidelines are seriously comprehensive (aka long). As a result, and to all our benefit, the UX guidelines have been consolidated into a single PDF document.
"Use this index to quickly find the user experience (UX) guidelines that can help you create a great Metro style app. If you haven't already, you should start by reading Making great Metro style apps and Planning Metro style apps.
In this article
- Metro design style
- Touch interaction
- Snapping and scaling
- Contracts, charms, and capabilities
- Tiles and notifications
- Roaming to the cloud
That should be enough UX design guidance to get you started at least. The created date in the PDF is 8/14/2012, so at least the PDF is fresh.
Make sure you also check out the related Navigation patterns, Commanding patterns, Touch patterns and Branding patterns (some of which also have PDF's, but those are 3,4,5 pages, nothing like this 316 tome)