Several questions about Windows 10 and group policy have been raised and I gather the resources I use for this information.
First you need to download the Group Policy Settings reference guide. This Excel spreadsheet have all the information you want about settings available in Windows 10
http://www.microsoft.com/en-us/download/details.aspx?id=25250 and the file you want to download is Windows 10 ADMX spreadsheet.xlsx
Second thing you need to download is the new ADMX templates
http://www.microsoft.com/en-us/download/details.aspx?id=48257
Install this MSI on your computer and in the folder %ProgramFiles(x86)%\Microsoft Group Policy\Windows 10\PolicyDefinitions
you find the ADMX/ADML files you need
Third thing you need is to deploy the ADMX files in your domain according to this KB
https://support.microsoft.com/kb/3087759
[Update 2015-09-07] Thanks for the reminder, I forget to reference Windows 10 ADK and MDT, and here it is!
http://go.microsoft.com/fwlink/p/?LinkId=526740
Microsoft Deployment Toolkit 2013 Update 1
Important! Known issues to MDT 2013 Update 1
A bonus is the Group Policy search tool that is updated with Windows 10 settings
http://gpsearch.azurewebsites.net/
Also have a look at my previous posts in the same topic
http://deploywindows.info/2015/08/20/how-do-you-update-your-group-policy-admx-files/
http://deploywindows.info/2015/08/25/windowslocationprovider-error-while-upgrading-windows-10-admx/
DeployWindows 