Download the latest version provided by Lyall here (Newest version as of this guide is 0.0.4) https://github.com/Lyall/OPPW4Fix

Once downloaded, unzip the file into the game folder. This can be found by:
Right Click One Piece Pirate Warriors 4 in your game Library, select properties

Click Installed Files and select Browse

Unzip the file into the game folder. It should look like this in the end:

Once Installed, open OPPW4Fix.ini and change settings as desired.