Unless you use images or music from a copyright-free site, you will need to obtain permission from the copyright owner to reuse/ remix them in the format you would like. Often the hardest part is finding who the copyright owner is.
This site gives the contact details for many music and movie companies, as well as sample permission letters for you to use and adapt.
YouTube's policies
How to report content on YouTube
How to protect their privacy online
How to be responsible YouTube community members
How to be responsible digital citizens
Learn the fundamentals of digital citizenship through animated, choose-your-own-adventure interactive experiences, designed for grades 6-9. Invite students to explore digital dilemmas, make good (and not-so-good) decisions, and try out possible solutions through stories and mini-games - all without risking their real-world reputations. Discover how Common Sense Education's award-winning digital literacy and citizenship curriculum seamlessly integrates into blended-learning environments. Coming soon as an iOS app, Android app, and Edmodo app!