The final work needs to only use material that you the have rights to use. This is because the work will be published online (and no, the fact it is for education doesn’t mean you get an out, that only applies if the work is not published). If you want to use music then you need to make sure you’re allowed to. Creative commons licences are usually the simplest way to do this. Creative commons does not equal free to use though. All it means is that the rights are declared in advance, without needing to ask, unlike traditional copyright. It is perfectly possible to have creative commons licenced work that excludes any reuse. (A very good intro is this YouTube clip, and here is an outline of the different licences.