How do you transfer into a dummy account?
How do you unpack the RAR file, I tried but I could not do it
I'll start with the ZIP method first since most people seem to prefer that way. But for extracting the RAR, try downloading the latest version of WinRAR. It's a free program and will allow you to open up and extract RAR files. You can still use it after the trial period ends - you just have to wait a few seconds and close down the window telling you your trial period is over (mine ended a couple of decades ago).
-1- ZIP file method: First extract the RAR using WinRAR. Then find the save you want to use - in this RAR they're labeled by trophy, but each download around here will be different. Find the CUSA folder for the save you want to use. For this Doom game it will be CUSA02085. Check to make sure that the save files are DIRECTLY inside of that CUSA folder (sometimes you'll find another folder or two inside of a CUSA folder which means you have to keep going until you hit the right folder). In this download it's all good, just know for the future.
Take that CUSA folder and turn it into a ZIP file. Some free programs can do that for you. If you have Windows 7 or later, an easy way to do it would be to right-click the CUSA folder, then in the context menu that pops up, click "send to..." then "compressed (zipped) folder". Now you have your ZIP. Go into Save Wizard, then the resign tab, click the import button, and import that ZIP you just made.
Important bit is to always make sure that a ZIP you're importing is actually a ZIP, and in the following format:
ZIP>>>CUSAfolder>>>files
Second method, using a USB stick and dummy folder:
-2- First you'll need to extract the RAR, just like in the other method, and locate the save or saves you want to use.
Set up your USB stick with a "dummy" account to hold your downloaded saves until they're resigned. I'll describe the proper structure in a bit, but the idea is it's in the same structure as your actual saves you've copied from your PS4, and Save Wizard will see them when you go to the "resign" tab although will not see them in the cheats tab (unless you register this "dummy" profile but since you're limited to registering 3 Save Wizard profiles, you don't want to register this one). You put the saves on your USB stick, resign them right from that list (not the import button), delete them when you're done.
Put the CUSA folder - just one single folder, no other folders inside, onlythe PS4 save files inside - put that folder on your USB stick.
Since it needs to be in the exact same structure as the way PS4s actually save games to a USB stick, BUT in a different profile than your real one, the structure would look like:
USB stick drive>>>PS4>>>SAVEDATA>>>0000000000000000>>>CUSAfolder>>>files
The part that's all 0s can be anything you make up, really. 0s just makes it a bit easier to distinguish from your actual profile.
If you do it this USB way, you don't use the "import" button. The saves are just right in the "resign" tab and you resign them from there without importing. Importing is only for ZIPs. You can have Save Wizard delete each save as it's done resigning, which makes this way a bit easier for resigning multiple saves at once, to better keep track of what's done and what's not done.
Hope this helps.