How to play I Am Not The Thief!

About I Am Not The Thief!, from BoardGameGeek:

On a stormy night, the mysterious package arrives. The lights go out. When the power is restored, the lights flicker on to reveal that the box has been ripped open and its contents stolen. All of us have something with us in our backpacks, handbags, satchels, etc., but one of us is The Thief. The Thief must make up a story about why they have the stolen item to fool the innocent. The innocent use a prompt to explain why they have their item and try to catch The Thief! Each player has a card sleeve with a picture of there item that shows a picture of the item and a prompt for a story about why they have it. The Thief has a sleeve that blocks the prompt.