You're getting assistance with the dry fert method, so I'll leave that in their capable hands; I've never used it since I have natural low-tech systems.
To respond to your question about substrate: It is true that plants will grow and grow quite well in any substrate, be it gravel, sand, enriched or soil. The gravel has to be small-grain, the pea gravel is the largest you should use; the finer the gravel the better for rooting plants and encouraging a good organics bed. The gravel in your photo is pea gravel or perhaps a tad larger, and while this can work, it is not the preferred size; I found my substrate plants did better when moved to finer gravel than in my pea gravel tank. I have gravel tanks, sand tanks and one enriched substrate tank with Flourite (made by Seachem). More on this in a moment.
The "Laurite" you mention is I suspect Laterite, an iron clay substance. This used to be popular (in the 1990's, I tried it in one tank back then) but is less so now; it is spread on the bottom of the tank, and then gravel or sand added as the main substrate. It is only one nutrient, iron; and iron is a micro-nutrient and only one of 15 minerals needed, so you can appreciate that it is going to be minimal at best. The planted tank group has learned much since laterite was about the only thing used; in my view, and that of most of my planted aquarium colleagues, it is not worth it. An enriched substrate such as Flourite, Eco-Complete, Amazon, etc. would be more beneficial. Which brings me back to the above.
In a high-tech setup (using more intense light with CO2 diffusion) there is likely an advantage to an enriched substrate. But they are expensive compared to fine gravel or sand, plus some of them have other issues related to their sharpness. I would not recommend Flourite or Eco-Complete in a tank with corys, loaches, and similar substrate or burrowing fish. I hold this view both from personal experience and from advice from several authorities. The other brands I have not tried or seen locally.