Okay. I am able to extract those files, but I don't know how to put them back in the same .mpq file again. If I can change those files, and put them back to the .mpq together with the listfile, maybe I can retain both the changes I made to the map, and both the original scenario objectives. Because when I attempt to play those campaign maps in custom game, they had no scenario objectives anymore.
Edit: I tried deleting the old campaign map in .mpq, and readding the modified .pud into .mpq. But when I tried to open the mission in campaign, it gives critical error and crashes.
Edit 2: This time, I didn't open any maps with world editor. I opened 1st mission of orc tides of darkness campaign with udtaed, and made some unit stat modifications only, to see if it would work this time. But when try to open the mission it still gives the same critical error. My work is getting desperate here.
Plus, I didn't understand what exactly I have to do with the listfile. Do I have to add it to .mpq each time I opened/made a modification in .mpq file? Also I see multiple listfiles, one belonging to the original game, and one that you probably sent me. It's confusing.