I will give this a shot:
Mimi, you need two open windows for this.
The first window is Basenotes - Your composing box. The cursor should be blinking at the spot where you wish to put the video.
The second window is www.youtube.com and you select the video you wish to bring in. Listen to the video. At any time during the listening, you can start importing.
The URL of that video is showing at the URL line. Highlight that whole line, in blue. Stay there and right click. Pick Copy.
Minimize the Youtube window, and
Go back to your first window, Basenotes composing box. The cursor should be blinking where you want to insert. On the top bar of the composing box, next to the little tree is a rectangular symbol ("insert video symbol"). Click on that.
Into the line URL field, you right click, and pick Paste. Click OK.
Good luck. Please try this out, right here, and we shall see whether this works.