Let me see if I can help you answer your own question.
Do you understand the difference between "to lie" and "to lay"?
If so, do you know the past forms of each?
If the person simply reclines, which verb is that?
What is the past form of that verb?
If a person sets something down (including him/herself), which verb is that?
What is the past form of that verb?
It will be easier for you to get it right next time if you work though this yourself. Many native speakers struggle with lie/lay as well.