Turn off App Updates
When you upgrade to Windows 10, it "helpfully" makes all Windows Store Apps update automatically.
To turn this off, run the "Store" App. It's the one with an old lady's handbag as the logo.
Click on the icon with your avatar in it. (Because that's obviously where they'd put the settings. Must've run out of Gear icons.)
Don't select "Downloads and updates" because why would you go there to change the way "Downloads and Updates" work?
Instead select "Settings".
In there you will see "App updates"
Turn "Update apps automatically" to Off.
Turn everything else off while you are at it.
Maybe turn off your computer too. You know you'll be happier for it.