Content for Short and Long Description
You will see a tab called "Content" in your product details
Short Description is for the text under the "Add to Cart" button (recommended max 320 characters)
Description is for the text under the item image, put your longer item description or return/exchange/refund policy here.
You can add links in here
You can add images in here (although you might need to do some HTML to include them and host the images somewhere else)