Since the FAQ web part is versatile, you can use it for questions and answers or to expand and collapse content.
When you click Add New Item, the fields in the web part are Question and Answer, but you don't have to use the Question field as a question -- you can use it as a header and the Answer field as a content area.
Never leave the Answer field blank or save an empty FAQ item. If you don't have content ready for an item, use placeholder content like "coming soon" -- leaving an FAQ item blank will cause errors on the page.
Use short questions, titles, and phrases in the Question field -- long ones will wrap down and are harder for the user to skim. Keep it short and simple.