String of Hearts like heat and bright light but they don’t tolerate direct sunlight. They can be placed indoor in South or West facing window with a lot of light and if outdoor, they can be in bright shade area. One of the easier ways to see if they get sufficient light is to see the color of the leaf and the gaps between leaves: String of Hearts leaves will be wider apart and lighter in color with less marbling if the plant needs more light.
If you want to grow string of hearts indoor make sure you give them the brightest window possible and keep the temperature around 80 to 85 degrees, 60 in winter time.
String of Hearts water need is just like other succulents, so make sure you give them a good soak after the soil is completely dried out from the last watering. In the winter, the plants need even less water than summer.