You cannot open "Part 10" on its own; you must have every single part (Part 1 through the end) in the same folder to extract the game.
This represents copyrighted material distributed without authorization. Conan.Exiles.Complete.Edition-CODEX.part10.rar
Because modern games are massive (often 60GB to 100GB+), they are typically split into smaller "RAR" archive parts to make downloading easier and to prevent a single connection error from ruining the entire download. "Part 10" is simply one segment of a much larger multi-part archive. You cannot open "Part 10" on its own;