These like bright indirect light, as direct sunshine can burn the leaves, so if you have a southern facing window make sure to have a sheer curtain or keep the plant farther from the window. Philodendrons are known to tolerate lower light levels, but tolerate does not mean thrive, so if you want a really leggy plant with small leaves, then low light works just fine. The best thing to do with plants is to mimic their native growing habits, which in this case means bright indirect light.
Water these when the top couple inches of the potting medium is dry, but never let them sit in water as that will lead to root rot. I generally don’t water mine until the potting medium has just dried out completely, but hasn’t been fully dry for an extended period of time. Make sure to water them fully so that water is running out of the drainage holes. During the colder months make sure to water a little less often, which basically means definitely let the potting medium dry out fully before watering again.
A fast draining, but good quality potting medium is the best way to go. I generally just make my own using equal parts worm castings, orchid bark, perlite, and horticultural charcoal and sphagnum moss if I have any of either on hand. When you re-pot yours, make sure that the size of the pot isn’t too much larger than the root ball, as this can lead to the roots being exposed to too much moisture. Always go up a size so that there is about an inch or so of room between the roots and the inside of the new pot.
Feed these a mild dose of a good quality, rounded 20-20-20 fertilizer during their growing period, and sparingly during the colder months when they aren’t growing as actively.