I would recommend that you start off small by buying some potting soil, and go around to places like hardware stores like Home Depot or Lowes that have gardening sections i.e. plants, maybe walmart, or ideally a local florist or greenhouse. Buy like 6 or so plants that you think look neat, make sure to read the instructions that come with the plant on those little cards, and either put them in the ground or get yourself some nice pots to replace the cheap temporary one's they come in. Some basic advice from a green thumb; Most plant's will be off just fine with a descent watering once a day or maybe every other day. If something is starting to look bad, chances are you are over or under watering it, if the soil is bone dry, or too wet, you know what the problem is, water more or cut back accordingly. Almost all things that grow in the ground are way more hardy and strong than you think, and can handle a lot of abuse, as long as it doesn't die outright you will very likely be able to save it and get it back to health. If you have a dog or something, don't let it pee on your plants, that will certainly kill them.