Like Rosebud said, starting with good soil is very important--it is where the roots live. Most native soils are not good enough without adding a lot of amendments. I do not know what you have available in Chile as far as commercial soils and/or nutrients--have you looked around?
First through you need to decide if you want to grow organically or use synthetic nutrients. The advantages of organic is that you do not have to be concerned with pH (unless it is way way out of whack), you can make teas out of a lot of different things, and there are a great many good organic soil recipes here--you can surely find one that you can get all the ingredients for. Organic is organic though--just like you cannot be kinda pregnant, you cannot be kinda organic. Synthetic nutrients can kill the microbes that are necessary to a good healthy organic soil.
Why don't you give us an idea of what you want and expect from your grow, how large you want it to be and what you have available where you live. Rosebud is great with organics, should you decide to go that way.
You do not want soil that says is feed the plant for x number of months or anything that says it has moisture crystals in it to keep the plants moister. There is an exception--some organic soils will feed the plant for several months, but as they are organic soil, this is different than for non-organic soils. Also, new plants do not need any nutrients at all at first. Feeding them when they are too young can kill them. Most people start giving nutrients at 2-3 weeks, unless you are using an organic soil meant to feed the plants (the soil feeds the plants, not added nutrients).
There is a lot to learn with this hobby and the more you know, the greater chance you have of a successful grow.