Ensure all files are in the same folder and have identical names, except for the part number.
The file name indicates it is the third part of a larger file ("part03.rar"). RAR archives break large files into smaller chunks to make downloading easier.
Select "Extract Here" (or "Extract to [Folder Name]") using WinRAR or 7-Zip.
Do you have all the other parts (e.g., .part01, .part02) in the same folder?
If prompted, enter the password provided by the source where you found the file. To give you the most accurate guide, could you tell me: Where did you download this file from?
You cannot open or extract this file alone. You need all parts (e.g., .part01.rar , .part02.rar , .part03.rar , etc.) in the same folder.