I think you mean like how I have my profile? This is the code I used:
<iframe height="0" width="0" src="https://www.youtube.com/embed/WPw7nlluRdc//?&;amp;;autoplay=1&;loop=1&;controls=1" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen="" loading="lazy">
</iframe>
In this part, /WPw7nlluRdc//, you wanna add the last part of the youtube link you get when you press share on whatever video/song you're using. You can change the width and height if you want it to be visible.