There are a couple ways. This is a quick and dirty of what I got to work. I will not provide links for any of this.
You will need:
PSN Liberator 1.0 ( Everywhere I got this, Avast flagged one of the files with some sort of infection. It's a false-positive)
klics.txt - contains licenses for a large amount of games, but not all
Game contents transferred from PS3 to PC - These are stored in folders by ID in /dev_hdd0/game
act.dat transferred from PS3 to PC - This is stored in /dev_hdd0/home/0000000x/exdata/
.rif & .edat files transferred from PS3 to PC - These are stored in /dev_hdd0/home/0000000x/exdata/
Extract PSN Liberator to a folder
Put klics.txt in the Tools folder
Put act.dat in Tools/exdata
Put the .rif/.edat files in a folder - it doesn't need to be in the folder with PSN Liberator, but it can be
Open PSN Liberator. It should ask you to specify where the .rif/.edat files are and maybe some of the other stuff. Most of it will not need to be set. When it's done, the 'RIFs and RAPs DIRECTORY' should be set. Make sure to set an output folder. Select 'PSN Game Folder' and choose the folder where the game folder you transferred is stored. There are buttons at the bottom to choose the output type. For this method, both PKG and ISO can be used.
If it works, the logs should say SUCCESS for each part of the process. If it fails, it will tell you why. If you end up with a box prompting you to enter something but the text is cut off, then the game isn't in the klics.txt file. I haven't been able to figure out it's asking for. Otherwise, you should end up with a pkg or iso file.
I may have left something out, this was just off the top of my head.