For the first release of Window 10 Technical Preview, Microsoft has put together the “Windows Technical Preview Quick Guide”, it’s a PDF file freely available to anyone, which you can download from the link at the bottom. And it explains how preview works in comparison to previous releases of Windows and how the new Windows Insider program works.
The guide continues describing the new features such as the new Start menu, how to use Universal apps in the desktop, Snap windows, the new Task View and in general how to move around Windows 10 with the new changes.
It’s not a complete eBook, but it’s something that can get you started if you’re planning to test drive the operating system.
Source and download Microsoft