Carbon is egg boxes, paper, cardboard, news paper, great place to get rid of shredded paper, dry leaves, sure you get the drift. The nitrogen is going to be most of your food scraps. You should try have a balance of half nitrogen half carbon.
I once worked in a hotel kitchen and we decided to get a worm farm. I felt much better about feeding the worms and providing our herbs with the nutrition they deserved and it barely even smelt. Worm bins are probable the most common form of indoor composting. It is important to keep a good mix of carbon and nitrogen.
There are tutorials online which show you how to make your own compost bin or you can go the easy route by just buying one. You can find red wigglers (the composting worm) at a bait shop.