I have MacBook Pro, tried to updated macOS. Result is “installer resources not found”. How do I quit installer? Command-Option-ESC does not respond.

command Q for quit

Or

from the drop down menu, Utilities/ or Installer ( in the upper left)> Quit.

Interesting you are in the installer but the error is “installer resources not found”.

The installer is sitting in your Applications folder "Install macOS High Sierra.app". I guess you could try again, however if it is corrupt somehow, your best bet maybe to download a new installer. (Maybe a slow internet connection is at fault?)

If you delete it, you can down load it again from the App store. Maybe make a bootable USBinstaller before you proceed.

How to create a bootable installer for macOS - Apple Support

Always advised to have an up to date backup plan— How to create a boot clone