The easiest way to start is to buy tomato plants from a nursery. Plant them where they will get lots of sunlight. They require a rich soil so dig a lot of animal or bird composted manure into the ground. Plant them deeply, so that part of the stem is underground -- roots will grow from the buried stem. Water them whenever the ground is dry. If you use tobacco, wash your hands before touching the tomatoes -- tobacco has a virus that kills tomato plants.
Tomatoes come in 2 styles, determinate or shrub-like, and indeterminate or vine-like. The 2nd produces more tomatoes but they need a trellis to climb and you must tend to them nearly every day, tieing them to the trellis to keep them off the ground.
Tomato plants grow suckers, secondary branches that grow in the axis between the stem and the leaf. Some people remove them and some people don't. Suckers become smaller branches with more tomatoes on them. You choose between more, smaller tomatoes and fewer bigger ones. Pick the tomatoes when their color shows they are ripe -- bright red for most varieties.
Indeterminate tomato plants will grow and produce tomatoes until the plants are killed by frost. When frost is likely, gather all the tomatoes, even the green ones. The green ones can get a little ripe in the house but they don't taste very good, especially after a summer of vine-ripened tomatoes! But they are good for making pickles, and there's a Southern US food, fried green tomatoes, that has a charm all its own. Also pull out the tomato plant and put it on your compost heap.
Then there are heirloom tomatoes. These are varieties that for lack of a better term are "antique". Passed down from generation to generation. IMHO, these are the best tasting tomatoes, although they might not be as pretty as the hybrids. Remember hybrids are bred to give big good looking fruit, while heirlooms don't necessarily look good, but taste GREAT.
I dont' know what you climate is like, but here I have already sown seed, and have many seedlings. They will not be planted out into the ground until about mid May, because of the danger of frost.
Are tomatoes generally grown there, and is there a source of seed or plants?
If any of the above info is confusing, or you'd like more concise information, please feel free to be more specific in your questions. There are lots of tomato growers here and we'd all be happy to help!