Soil building is absolutely a headache at first, but most of it is trying to understand why things are necessary.
You can basically make a workable soil with pretty much anything as long as it fits the “theory” of soil building, but certain ingredients are more premium than others.
You need a base, which can be dirt, peat, coco coir, straw, or anything that roots can grow through and that can hold water and nutrients, without drowning the roots.
You need some kind of aeration, like pumice, perlite, vermiculite, rice hulls, or anything that will give pockets of air and loosen the density of base. Even hard shell pine cones can work in conjunction with another aerator.
You need the main nutrients- Nitrogen for vegetative growth, Phosphorus for flowers/fruits, and Potassium for overall health and root/cell development. Potassium regulates the turn over of intake, usage and building too, so plants can grow stronger and faster. Oxygen, carbon and hydrogen are also main, or “macro”, nutrients, but they are more naturally occurring and so aren’t really a concern for soil. Many natural fertilizers have varying nutrient ratios, so you have to look and decide what you need.
You need calcium, magnesium, and sometimes sulfur, but in much smaller quantities. Micronutes in even less quantities can be copper, iron, zinc, and some other things… but those are the least important for a basic soil. A quick google search can help tell you what to add to get some of each thing. Something like egg shells or bone or shell flour can work for calcium, and a simple decomposed banana can help for something like potassium. For rock dust, stick with basalt… it’s cheaper and has less overall toxins/heavy metals than other rock dusts.
Something like dolomite lime is calcium magnesium carbonate and can assist in balancing ph.
Plants cannot absorb anything until it breaks down to a basic form, so often times super soils will actually be better on the second use, when everything starts to gel better.
Then there’s a bunch of stuff for root health… microbes help break stuff down and give a clean boost to growth, and fungi help expand root growth which leads to better intake, but I’ll leave that to another to explain.
mixing it… this is where it can get tricky, because if you don’t mix it right, or if you are too wild with your mix, it can be too strong, too weak, or throw your ph way out of wack… which can lead to a bunch of problems… if ph is too high, it won’t let certain things be absorbed, and if it is too low, it can allow toxins to be absorbed.
Almost every individual ingredient can be switched out for another ingredient that does essentially the same thing, but as stated at the beginning of this long-ass post, some things are more premium. Bat guano and seabird guano are one example. Compost vs worm castings is another.