Checkend Sample Product
This is the description under Tab #1.
You precede it with a "Heading" tag. In this case, it's a Heading 4 tag (in HTML code).
You can add links here, images, and even videos. Pretty much anything that you can add from within the Shopify product editor.
This is the description under Tab #2
If you want more quantities of this product than are currently shown, please contact us at email@example.com and we will be more than happy to try to accomodate you.