Enable developer mode on your PC at Settings > Update & Security > For developers. See current release notes for information about the newest mixed reality features available with each release of Windows 10. You can install the most recent version of Windows 10 via Windows Update in Settings or by creating installation media, using the link in the left column. Install the most recent version of Windows 10 so your PC's operating system matches the platform for which you're building mixed reality applications. Bookmark this page and check it regularly to keep up-to-date on the most recent version of each tool recommended for mixed reality development.