Destination City (if applicable)
Click on quantity, to focus (quantity is focused when page loads)
Use up/down arrow keys to select quantity
Press the TAB key (focus will move to description)
Type in the description of your item. As you type, suggestions will appear. You can use the up/down arrow keys to scroll through the list.
Pressing the TAB key while typing or in the suggestion list will create a new item row and set focus on the quantity field
Repeat (starting at #2)