1) Download AddmusicK 1.0.5
Download link: https://www.smwcentral.net/?p=section&a=details&id=14717
2) Open up the music folder, go to "originals", select the "05 Starman" file, right click, click copy, and paste a copy of it on your desktop (just in case something messes up)
3) Open the "05 Starman" file, then minimize it.
4) Find the .txt file for the custom music that you want, open it, press Ctrl+A, then press Ctrl+C.
5) Go back to the "05 Starman" file, press Ctrl+A, then press backspace. Then, press Ctrl+V. You should see all of the contents from your custom music file.
6) Save the file, open AMKGUI, click "Add a song" on the side, find the "05 Starman" file, double click, then at the bottom click "Run", select your ROM, and eventually a message should appear telling you that there were no problems! (Unless there were problems, of course.)
7) Open your ROM in Lunar Magic, place a star, (unless you already have one) then save the ROM.
8) Run the ROM in your emulator, get to the level, collect the star, and there you go! It's that simple! Hope this helps