Follow these steps to download Technical Preview:1. Sign up for the Windows Insider Programme, if you haven't already.
2. Read the system requirements.
3. Click on one of the Download links on this page to download a special file – called an ISO file – that you can use to install the preview.
4. When the download is complete, transfer the ISO file to installation media such as a USB flash drive or DVD.
5. Boot your PC from the installation media, then follow the steps to perform a clean installation.
Windows 10 build 10049http://windows.microsoft.com/en-gb/windows/preview-iso-update-1503Install from USBhttp://www.intowindows.com/install-windows-10-from-usb-drive/