Could you explain that a liitle more please, Theland?
Are you trying to embed a Youtube video into an AB page or are you trying to save a Youtube (or other) video to your computer?
If it's the former, and you're using a Windows PC or laptop, you need to IGNORE the 'Share' button on a Youtube page. Instead, you should copy the URL that appears in your browser's address bar. (Click on the address to highlight it. Right-click and select 'Copy'). Then come to an AB post, right-click where you want the video to appear (preferably allocating it a separate line to anything else in your post) and select 'Paste'.
Note that the foregoing won't work on mobile devices (such as iPads and phones) because the address will take a different form. (You need to be using one that includes 'youtube.com', rather than one with 'youtu.be' in it).
If you're trying to save a video to your computer, there are three ways of doing it. One uses a browser extension (so we'd need to know which browser you use), one uses a specific program that you install onto your computer and one inlvolves making the use of online copying services. Further info available on request (if that's what you're trying to do).