Hello there, @chrispe80 ...
If you are adding YouTube videos to your Canvas Studio library, there is no way to edit those videos. Often times, when you are adding videos from YouTube, they are not your own videos, so there would be no way to edit those. Studio is essentially making a link that points to the YouTube video and adds a layer over the top of the video when viewed within Canvas which shows the Studio video controls.
I'm assuming that the quizzing permission of Canvas Studio is turned on by your school's local Canvas administrator? If not, you might want to have a conversation with that person. This is the Guide that your Canvas admin should look at to turn it on: How do I manage user role permissions for a Canvas... - Canvas Community.
I hope this info will be helpful to you. Sing out if you have any other questions about this...thanks!
