Final answer:
Doctor Jenkins prepares for the return of the musician by setting up a phonograph in his room.
Step-by-step explanation:
In the short story 'The Portable Phonograph,' the character Doctor Jenkins prepares for the return of the musician by setting up a phonograph in his room. He makes sure that all the arrangements are properly fixed by workmen under his direction. The phonograph plays an important role in the story as it provides a sense of comfort and connection to the beauty of music in a post-apocalyptic world.