Open the YouTube video you want to embed, then click on the "Share" button.

In the share options, click on "Embed." You will see a screen with the embed code.
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Click Copy to save the code to your clipboard.
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Navigate to the size chart you want to add the video to.

At the bottom of your size chart layout, click on "Add layout block" and select "HTML Code."
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Paste the embed code into the HTML code block. You will see a preview of the video at the bottom of the size chart layout.
​Feel free to adjust the width and height to fit your layout.

Don’t forget to click Save to ensure your video is embedded in the size chart.