Find the folder where the profile of the opera is stored. Usually for niksov it is ~/.opera/1 , for windows - %AppData%\Opera\Opera\profile2 .
We put urlfilter.ini in the profile folder, replacing the existing one. Then in this profile folder we go to the styles / user subfolder and put the adblock.css file there.
We launch the opera, and in the menu → select Ad Blocker (By ELV1S) .
Enjoy the Internet without advertising. Almost. ;)
_____
That is /home//.opera/ .
%AppData% for different systems different. Just enter the specified address in the address bar of the explorer.