You must have every part (e.g., part1.rar , part2.rar ) in the same folder before starting.
These are standard "2K" textures, which are less hardware-intensive than the 4K alternatives. Download File kb3d_dieselpunk.png.2k.part2.rar
Because this is a multi-part RAR archive, you cannot extract "part2" on its own. You must have every part (e