The string of hearts is a semi-succulent plant, which means it is more tolerant of dry soil than wet soil and is prone to rotting in wet soil.
You should water it sparingly, if in doubt. You can always add more water. You can confidently allow the soil to dry out completely between waterings.
LIGHT: 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