How do you get a record on Animal Crossing ww

On a Saturday night, between eight and midnight, go to the Roost which is located at the museum. There will be a dog named K.K. Slider there singing songs, after he sings a song he will give you a copy of it to play at your home. After a while he will begin asking you for requests, where you can then access secret songs such as Stale Cupcakes.