1. Clear the plot of ancient bhikkhu ruins : go to the Altar of the Sun to find information about the ancients.
2. Go to the Altar of the Sun : Find the underground entrance at the Altar of the Sun and enter the secret passage.
3. Enter the secret passage : Uncover the secrets of the ancients.
4. Break a jar to create a magic circle : Use a broken jar to create a magic circle in the secret passage.
5. Use the power of the Vulcan paper to rescue the ancient man Bio : Use the power of the Vulcan paper to rescue the ancient man Bio.
6. Return to Chinobio Town : Return to Chinobio Town from the No. 3 Travel Water Pipe outside.
7. Find Captain Bio : Find Captain Bio in the museum in Tonobio Town.
8. Set off with him : Set off with his submarine to get nautical charts.
After completing the above steps, you can find Captain Bio in the museum and set off with him to obtain the nautical chart.