Do you upgrade to Windows 10?

I've heard some people can force this upgrade.
You need to check for Windows updates, install updates if any. Check your history and look for KB2952664 for Windows 7, or KB2976978 for Windows 8. Installing this has triggered instant downloadingfor some people, if it's already installed then you should wait.
If you have failed updates in the history, with "Upgrade to Windows 10" FAILED then you are not in the first wave. You'll get the update later in the day, or later.

To check if you're ready to install;
Check for a folder called $Windows ~BT in your C:/ (enable view hidden files). If this isn't present, you aren't ready.
To check if you're downloading;
Go to C:/Windows/SoftwareDistribution/Download. If you have a folder called Install, then you're downloading Windows 10.

If you have neither, and those updates are already installed. You have to wait.

P.S If you have the Install or $Windows ~BT folder, do not execute or edit anything within them. Trying to run setup.exe will result in an explosion :hurr: srsly tho, don't run it.