Custom Music Tutorial

It seems a lot of people have been asking this, so here it is.
1. Download a MP3. Put it in the world's folder.
2. On SMBX, go to Level Settings, Misc.
3. Write in the little rectangular box you see. Include the music you want to have in your level, and remember to add .mp3 to the end of your music name.
4.Then click "custom."
It's magical!

I just want to point out that it's impossible to use two custom music files in the same section of a level.

I know.
What made you say that?

You forget that :P

It SHOULD be obvious, since there's only one MP3 box in the music window in the SMBX Level Designer.

I don't know why so much people are telling me to put in the post that you can't use more than one custom music in a section... It's totally obvious.