PES 2018 CA River Plate MiniFace Pack by RKH257
Copy the file RIVER PLATE MF_RKH257.CPK to the download folder where
installed the game.
Generally found in:
C: \ Program Files (x86) \ Steam \ steamapps \ common \ PRO EVOLUTION SOCCER 2018 \ download
Generate the DpFileList.bin file with DpFileList Generator (by Baris).
Link if you do not have the application: here.