You generally cannot open "Part 3" by itself. You must have all parts (Part 1, Part 2, etc.) in the same folder.
It looks like you are looking at a for a repack of the game BONELAB . Since this is Part 3 , here is what you need to know to handle it correctly: Important Notes for Repack Archives: BONELAB [ScOOt3r Repacks].part3.rar
BONELAB requires a VR headset and a decent PC (GTX 1060 or better) to run smoothly. You generally cannot open "Part 3" by itself
If Part 3 gives you a "Checksum Error" or says the "archive is corrupt," it usually means that specific file was interrupted during download. You may need to redownload just that part. Safety Check BONELAB [ScOOt3r Repacks].part3.rar