As a whole, this is a pretty advanced topic for a beginner, but it can be broken into distinct parts that taken individually are not that formidable. As with any complex problem, I recommend breaking it down into smaller, manageable parts, coding what you can. Most of the program you've described is object or file management, including the use of collections. To simplify, you could start by ignoring the .mp3 (or audio file) part of it and simply write the code to manage the objects, writing other method stubs to do the audio functions with comments that describe what they'll do when put together with a player. For example, you might write a void playMP3() method that takes an .mp3 file as a parameter and then simply prints:
Playing MP3: <fileName>
and then similarly for the other player functions.
When ready to add the .mp3 functionality, search "java mp3 library" (or similar) and explore the available options for adding what you need, then integrating it with the methods you plan to write, filling them in with the needed code to use the chosen .mp3 library.
Come back with more questions as needed.