Place them in the packages folder of your USB. Go to Package Manager > Install Package Files > Standard on your PS3 to install.
Copy the PKG to the root of an NTFS-formatted USB drive.
When users search for they are usually looking for a full, pre-packaged version of the game that can be installed on a jailbroken PS3 (CFW or HEN) or the RPCS3 emulator on PC.