Right-click on the first file ( 478_1_RPA.part1.rar ) and select "Extract Here" or "Extract to [folder]" using your software.
The software will automatically detect the other parts, connect them, and extract the complete contents. 478_1_RPA.part1.rar
Make sure you have all files in the set (e.g., .part1.rar , .part2.rar , etc.) located in the same folder. Right-click on the first file ( 478_1_RPA