Install the APK. Run the game wait a minute close the game, Move the archive.rpa that was with the apk to:
documents/Ixalon/com.caribdis.eternum/game
When you lunch the game it makes them for you, I guess you have to make them manually. Go to "documents" folder make a new folder name it "Ixalon" open it make a new folder then name it "com.caribdis.eternum" then "game" folder and copy/paste "archive.rpa" into it. You don't create the Documents folder it should be there.