In a multi-part set, all parts (Part 1, Part 2, etc.) must be in the same folder before you can extract them. You generally only need to right-click Part 1 and select "Extract Here" to unpack the entire game.
This stage usually covers the transition from Norway to England, where Eivor and the Raven Clan establish their settlement, Ravensthorpe . AssassinsCreedValhalla.part5.rar
If you are looking for what typically happens in "Part 5" of a playthrough or walkthrough: In a multi-part set, all parts (Part 1, Part 2, etc
"AssassinsCreedValhalla.part5.rar" appears to be a specific compressed file segment from a multi-part download, likely for the PC version of the game. Due to its massive size—requiring about of storage space—the game is frequently split into many "RAR" parts for easier sharing or downloading. In a multi-part set