You need to lose to get his GO and then talk to Ran. He will give you a hint. Then you talk to Reynard and Vic. Vic will teach you how to win the fight. Now you just need to use the new option and test the best combination to win.
Kubas only appears aftee you defeat Iron. As for the combinations, you should be able to do so after the training with Reynard and Vic. A new option will be available for the fight. After you choose that one you can use the 3 combinations to win.