(e.g., is it a game download, a backup, or a file from a website?)
Knowing this will help me provide the exact steps or information you need. mk.part1.rar
(e.g., are you missing part 2?)
You only need to open/extract mk.part1.rar . The archiving software (like WinRAR or 7-Zip ) will automatically detect the other parts and join them to extract the complete file. is it a game download