I keep meaning to move the below post to Player Squared, but in the meantime here's a link with a text tutorial that goes into a bit (too much) detail on resigning. For the RAR files, I have always recommended WinRAR because versions in the 5.70s and above present the least compatability issues with Save Wizard, but I don't believe there's a WinRAR version for Mac. WinZIP has a Mac version and it should work just fine the great majority of the time. Use WinZIP to unpack the RARs.
As Hopper helpfully pointed out, the bin files are the save files themselves, or at least part of them. Each PS4 save file consists of two PC files: a bin file and a file with an identical name but no extension ... and so small that some operating systems won't even display the extension-less files. Not sure how a Mac would display them. But if you're just seeing a bin file, not in a ZIP, then you want to take the CUSA folder that it's inside, and ZIP that CUSA folder. Then, in Save Wizard, import the ZIP. WinZIP is actually not the best option for creating the Zip as it sometimes messes with the filepath, so if the Mac OS can create ZIPs without any special program then just try that.
Anyway, more detail in this link. One of these days I'll move this over here...
FAQ & Troubleshooting Thread (PS4 Game Saves)
- NextGenUpdate