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.
When creating items for the web part, don't leave any of the Answer fields blank. If one of them is blank it will cause odd sizing and other issues with the web part.
If you need to leave one blank and come back to it, just click your spacebar a few times, click your enter key, and/or add a period or dash in the field as a placeholder.
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.