This question is asked too often. Here's the simple answer for anyone who wanna add mp3 but dont know how to do that.
First, you need to get the mp3 URL.
- How do I get the mp3 URL???
There are some websites that provide music URLs, try to search for it, or ask your friends. If you have the mp3 file in your computer, you need to upload it on a webserver to get the URL. There are a number of sites that let you upload files (like myfilehut.com, filelodge.com, ripway.com, etc.), make sure they give you a direct URL to the file and allow hotlinking.
Once you have the mp3 URL, one of the simplest way is to use the music code generator and add the generated code into your Media/Now Playing section.