Right-click ( part01.rar ) and select "Extract Here" or "Extract to [Folder Name]" . The software will automatically pull data from part02.rar and the remaining parts.
Because it is a "part02" file, it cannot be used on its own. You must have all other parts (part01, part03, etc.) in the same folder to successfully extract and install the game.
Repacks from sites like Game3rb are unofficial distributions. Always ensure you are using a trusted source to avoid malware. If you'd like, I can help you find: The official system requirements for PayDay 2. A list of essential mods for the game. Information on how to update a repacked version.
: This usually happens if your antivirus deleted a file during installation. Check your "Quarantine" folder to restore it or reinstall with the antivirus off.