I have several orchids in my greenhouse, which is adjoined to the house on the south side. Orchids are actually quite sturdy plants, although getting them to bloom is another matter.
You can find complete instructions on raising all types of orchids here:
Care of your Hausermann Orchid Cultures
If you don't know what type you have, you can look at pictures on this site and figure out what you have. If it has a big bloom, it's probably a cattlea, although not all cattleas have big blooms. The orchids you often see in Walmart are usually phaleanopsis, dendrobiums, or sometimes species orchids.