Simple to make luminarias.
Luminarias at Christmas in Albuquerque, New Mexico, Old Town.
Sand. For stability and to hold the candle. About 2 - 3" of sand.
Luminaria Candles or Tea Lights.
Here in the southwest we double fold the top, however, I have seen them simply cut with a cute pinking shear across the top of the bag.
Again, anyway you use them they are great.