How can I turn off Windows 10 doing updates?
This has become difficult. You can change when it will do reboots after the updates. You can also defer updates but security updates will still be applied.
But you can't set a date or time to next do an update. If you want to turn updating off completely you have to go into the Services options and find Windows Update. Then disable it. Remember this will stop all updates including security updates.
To defer updates go to the Settings, Updates and Security, Windows Update, Advanced options, and check Defer upgrades. Be very careful if you must do this.