Main Story
Meet the Veiled Lady again at the shed after nightfall.
Wait until the Next Night.
Light the Candle under the Shed.
Advance to the following night through the Time menu, then light the candle under the shed.
Talk to the Veiled Lady.
Inspect the Painting.
Approach her beside the well. Inspect the painting on the mural, then speak with her again to begin the next scene.