You use PakBuild. The FPK file is the file to unpack.
Click the PAK menu on the menu bar.
Select the "Unpack..." option from the dropdown menu.
Navigate to and select the Assets0.fpk file.
Click on "Open".
Select the location to unpack the file.
Unpack the others too.
That should do it (I don't think I missed any steps, but I didn't check) - go to where you unpacked them and look at all the files (there are over 7,500 of them in many folders).