This super short video gives you a great primer on copyright.
Perhaps the least exciting thing about filmmaking is having to deal with copyright laws, but despite its lack of, I don't know, allure, it's something that must be addressed (unless you like getting sued). Aidin Robbins of Digital Blast manages to stuff information on creative commons, attribution, commercial, noncommercial, copyrighted, and fair use inside the 45-second video below, so if you're looking for a great introduction to copyright law but literally can't spare a single minute out of your day, you might want to check it out.
Even though the video is informative and an extremely economic use of 45 seconds, understand that it is just a primer. Unless you're a copyright lawyer, the rules about copyrighted materials, as well as how to go about licensing that material, can not only be difficult to understand, but can also change without you being aware.
So yes, research copyright laws, licensing, and fair use—these are topics we cover here often—but also understand that protecting your film, your company, and yourself means hiring an attorney. When it comes to using other people's music, footage, or other pieces of art in your films, it's always best to make sure you're not infringing on anyone's right to profit from their own work.