Plug the drive into one of the USB ports on your console.
Capcom released several patches (e.g., v1.05, v1.10) that fixed performance bugs, improved textures on the base PS4, and added the "Mercenaries" mode.
Are you trying to via USB?
Once you have obtained the correct PKG files, the installation process is straightforward. Below are the two most common methods, based on guides by community members.