Ficus elastica will do best in a well lit position with lots of bright light, it can handle dappled to full sun on its leaves for a few hours a day but if you start to see burnt patches or withered wilting leaves you should move your plant to a more protected position. Variegated varieties will need even more light than their non-variegated relatives as they have less of the green pigment chlorophyll available for photosynthesis.