Only extract part1 . Your extraction software (like WinRAR or 7-Zip) will automatically pull data from the subsequent parts to reconstruct the full installer.
Revachol is a real place with real challenges, and it is easy to find yourself "blocked" if you don't play your cards right. Disco.Elysium.v29.01.2021.GOG.part1.rar
If you are looking for more specific troubleshooting or want to see how the game has evolved, check out the Disco Elysium GOG Community or the official subreddit for updated builds and community mods. Only extract part1