Knowing how to start a garden is not all that difficult. There are a few things for you to consider, such as where you're going to plant, the soil that you're planting in, how you will water your garden, the pest control that you will need as your garden grows, and the continuous addition of compost to your garden.
Where you plant should be a sunny area that is sized according to what you can handle. If you're starting a new garden for the first time, you may want to start off using a smaller amount of space, even if you have a large area to choose from. Once you find a sunny area and remove all the weeds, you want to amend the soil.
You need to have good drain, but not complete run off. The water needs to have the ability to say stay there a while, but not drown your plant roots, so you get a good mix of clay, sand and compost. Till your soil and then water the area well.
Next, consider how to keep your soil moist for your plants to drink. You will want to consider if you should use drip irrigation or sprinklers, and if you will have a system that's automated so that you can make sure your plants are tattered even if you're not home. Alternately, you need to decide if you're going to water them by hand, if you do not have the ability to put in a system, especially on that's automated.
You also want to consider pest control. The best way to control pests is by starting with what plants you choose to grow, and where you plant them. Different plants attract different insects, both predators and pests, so if you put together plants that attract predators of a pest that another plant has, the plants will work symbiotically together. For example lady bugs eat aphids, so put a plant that attracts lady bugs next to a plant that attracts aphids. A plant may not always attract a predator, but it can repel the pests of another plant too. Garlic is an example of a repellent plant. This is companion planting. You can also use combinations of soap, hot peppers and garlic to ward off pests.
Start a compost pile or bin. Make sure you are continually adding to it, whether it be from your vegetable scraps, your peelings, or your yard clippings, a variety of things can be added to your compost pile so that you can continuously add compost to your garden including it gets the nutrients that it needs.