Your plant is a Pachypodium (not actually a cactus). It likes lots and lots of sun, as much as you can possibly provide inside. The leaves may sometimes look a little the worse for wear during normal growth, not necessarily anything to be concerned about. As time goes on you will be able to appreciate the various phases it goes through.
As for other aspects of care... when the plant is leafy and growing, it likes regular water. Indoors that would be maybe once a week, given good drainage. More often if it actually gets hot (and especially hot and dry) indoors. When the plant begins to lose its leaves (usually late fall or early winter) start to water much less often, like when the soil is dry but not much sooner. During the cold, dark days of winter (sleepy time for your Pachypodium) you need to exercise restraint with the watering can because there is a serious risk of rot. As long as you follow those general rules your plant can have a long and healthy life and will eventually grow into a small tree in a big enough container.
