Ok don’t worry I’m assuming you know how to upload a video on youtube. Basically when you go on the edit window of your video on youtube there’s the option for the video to be private, public or unlisted. You need to click unlisted. It won’t appear on your you channel only the persons with the link will be able to see it. Private works the same way but the website of the school wouldn’t let the video play. So click on unlisted and everything will be fine.
I was in the same panic mode when I wanted to upload a video here. So I completely understand.