I reserved my copy of Windows 10 back a few weeks ago once I notice there was an option to do so. So it came out yesterday and I have Win10 on my laptop that had Window 8.1 x64 and still not had the option to do so on my desktop that has Windows 7 Pro x64 SP1 (legit) any way i can trigger the upgrade or do I have to wait till the a wave send out the upgrade process.
It should be deployed in waves. The upgrade is started from Windows Update. If it shows as available and it fails to update, then you will just need to try it later as Microsoft needs to flip the switch so to speak for you and has not done so yet.
I hit the Reserve button yesterday. Today I had an option on my Windows Update window to start the process. When I clicked on that button, it immediately downloaded the files.