How do you get regigigas Pokemon mystery dungeon explorers of time if you're a munchlax with a turtwig?

Beat the game after doing some extra quests Team Charm will come to the guide. Wigglytuff will go find a key in his office and team Charm will leave. Your partner then asks team Charm if you two can go on the expidetion too. Team Charm lets everyone in the guide go. Once you reach Aegis Cave you must find the correct stones from in side the maze. You get these stones by defeating Unknown. Once you have made it through the first puzzle you have to face regice. Then Regirock and then registeel. Team Charm will be defeated by registeel. They agree to help you fight Regigigas. Once you get through the last maze you reach Regigigas. He is aided by Bronzong and Hitmonlee so be prepared. Team Charm teams up with you but you can't control them. once u beat regigigas you will leave and a new cave is revealed. You can now go back in and fight just regigigas again and it may join your team. I suggest bringing a Friendship Bow to up your chances of recruiting it.