You can perform the following steps to add a YouTube video to a product or category page:

1. Login to your SEO-Cart account and navigate to the Product or Category you would like to add a video for.
2. Click the "Modify" link next to the product or category
3. On the description field, click the "Insert / edit embedded media" button on the WYSIWYG editor toolbar which is on the second row towards the right within the toolbar icons. If you do not see this button, make sure the "Show Advanced Options" setting is enable for your WYSIWYG editor.
4. A dialog box will open. Paste the YouTube URL in "File/URL" field. Leave the "Type" as flash and the dimensions should automatically set by themselves.
5. Click Insert and click the Update button towards the bottom right corner of the page.
6. Regenerate your store.