This is not for the faint of heart. If you are not computer savvy, you may want to spend the money and have an IT professional do it for you. If you're game, however, here are two websites that should help:
http://www.thewindowsclub.com/how-to...-in-windows-10
https://www.bleepingcomputer.com/new...tre-cpu-flaws/
PowerShell is a command-line program that's hidden away down in the Windows engine room for use by said IT professionals. You need to run it with elevated privileges, i.e. as Administrator, and the first website above will show you how.
The second link contains somewhat understandable instructions for downloading and installing the patch. Caveat - it will take hours and it ain't easy. (I've installed the patch on two Windows 10 machines and now I'm going to work on two Windows 7 machines. Please wish me luck.)