You create a sound or an image of an object within range that lasts for the duration. The illusion ends if you dismiss it as an action or cast this spell again.
If you create a sound, volume can range from a whisper to a scream. It can be any sound you choose. The sound is continuous or you can make sounds at different times for the duration.
If you create an image of an object - such as a chair, muddy footprints, or a small chest - it must be no larger than a 5-foot cube. The image can't create any sensory effects. Physical interaction with the image reveals it to be an illusion.
If a creature uses its action to examine the sound or image, they can determine that it is an illusion with an Investigation check against your spell save DC.