With the release of Windows 10 build 15014, Microsoft has updated the Store. Now you can get new themes for your Desktop using a special link in the Settings app, which will lead you directly to a new section of Windows Store dedicated to Themes.
To check out the new theme section, do the following.
- Open Settings.
- Go to Personalization - Themes:
- The page lists installed themes. Under the theme list, you'll find the link Get more themes online with the Store icon. Click it.
Browse for the theme you like and install it.