Questions about the Music you want to use:
WHO owns the music? Unless YOU composed it and recorded it, someone else owns it (and it's not always the person that wrote it). There are almost no audio recordings that are truly free (Public Domain) to use. If someone else owns it the law says you MUST have their permission (usually for a fee) to use it.
HOW do you want to use the music? If you want to use it exactly as it is (a full piece of music meant to be played to be listened to) that's one thing, BUT if you want to use it as a part of something else (a mash-up or remix; as part of a video or broadcast), the rules can change.
WHO is going to hear it, and WHERE will they hear it? If you are the project you are using the music in will ONLY be heard by you, or the teacher of a specific course and the students in that course, you're probably okay to use what ever music you want.
However, if you plan on uploading it anywhere beyond your class Canvas page, playing it for the whole school, or broadcasting it via JCTV, you need to find music that you have legal permission to use.
WHY does it have to be this piece of music? With some extra work and digging, you may be able to find something that also meets your need (SEE "What is the Creative Commons" or the other links on this page). If there's a very good reason why it must be that particular piece of music (you are analyzing it or providing commentary on it) your use might be Fair Use. (SEE "What is Fair Use" on this guide)
HOW much work are you willing to do, and HOW much are you willing to spend, to use the song? If you absolutely MUST use that copyrighted song for a broadcast, and it's not Fair Use, there are legal ways to acquire license/rights to use music. But they take time, require effort, and cost money. (SEE "Acquiring Rights")
Attribution Only (CC-BY)
Using music from these sites requires that you display attribution (credit) somewhere in your project. Most of the music is composed or collected by the owners of the sites, so you won't find current popular hits here. You may need to spend some time listening to find something that fits your need.
Royalty Free music for a Fee
Royalty Free Music (variety of Creative Commons Licenses)
For more information on Creative Commons Licenses, see "About Creative Commons"
Your best bet is to choose "Attribution Only" (CC-BY) or "Attribution-Non Commercial" (CC-BY-NC)
Reminder adding music to video counts as a Derivative Use, so you CAN'T use things labeled with a NoDerivs (ND) license.