Multi-part RAR files work as a single unit. You cannot extract part 10 by itself; you must have every part from through part10 (and any subsequent parts) in the same folder .
This guide explains how to manage and install the archive "Conan Exiles Build.26102022.part10.rar". This specific file is the 10th part of a multi-volume split archive containing a build of dated October 26, 2022. Step 1: Verify All Parts
Once extracted, you will likely have a folder containing the game executable ( ConanSandbox.exe ) and data files.