Hello and welcome to justanswer, My name is ***** ***** i will be assisting you today,
1-First open the Windows Start menu by clicking on the icon in the bottom left of the screen. Select Settings from the menu. : http://cdn2.pcadvisor.co.uk/cmsdata/features/3615606/Win10-DG-Step1.png
2-Now you’ll see on option for Update & Security. Click it. : http://cdn2.pcadvisor.co.uk/cmsdata/features/3615606/Win10-DG-Step2.png
3-On the next page you’ll find a list of options on the left, one of which is Recovery. Click this and the main pane will display a variety of choices. The one you want is Go back to Windows 7
4-You’ll now be presented with a screen asking you why you’re downgrading. Essentially, it's a tool so Microsoft can gauge the user experience with Windows 10. Click Next when you’re done.
5-Windows will now roll back your system to how it was before Windows 10 was installed.
You can also watch this tutorial video : https://www.youtube.com/watch?v=EOzfv6qszuo
Hope this help