You can download the install tool from Microsoft:
https://www.microsoft.com/en-gb/software-download/windows10
You can perform a direct upgrade which will work pretty much the same as the time delayed automatic install. The direct upgrade will automatically chose the correct flavor of Windows 10 to match your previous Windows.
Or you can make media, DVD/Thumbdrive. If you use the create media you need to chose the version of Windows 10 to the previous version of Windows you are running. If you start the upgrade from the media while your are within your previous Windows OS and the version matches, home or pro, it will perform the upgrade without prompting you for a key. If your version does not match or your are booting with the...