Although this video (3:07) has the signature Gardening Guy, it’s a gardening gal who shows us how it’s done. She makes it seem easy, but then all these gardening video types do that.
You get your little tomato plant (e.g. Health Kick which is high in licopine which is good for your, or Juliet which bears early fruit) and dig a deep hole for it in the vegetable garden. It’s important to add lime to the soil in order to increase the calcium content of the soil. This discourages a plant disease called blossom end rot. You need to add fertilizer as well.
You bury the plant deep in the hole so that some of its lower leaves will be covered. This encourages root development.
This gardener is quite keen on protecting young tomato plants from night frost, and demonstrates a number of devices for doing so. First, you get an old-fashioned glass cloche-type shelter for individual plants, then you get something called a Wall of Water, which is a plastic wall with cells you fill with water to create a wall around the plant. Presumably it waters the plant too. There is also a plain plastic shelter with an aeration hole at the top.
The Gardening Gal recommends a tall, square wire cage for staking the tomato plant. The vine-type plants tend to get rather rangy, so you need to contain them so the vine doesn’t crawl along the ground, where the fruit will rot. A cage makes pruning the plant and picking the fruit easy.