For Soil and Autos go the supersoil route to start.
https://www.growweedeasy.com/just-add-water-super-soil-grow-guide-easy-organic-weed
Check out kind soil.
There are two thing a plant will do in nature and it is beneficial to know how to use them, first is roots are programed to seek out water and overwatering is the biggest hindrance to their quick development. Root tips shootout growth in dry Pockets looking for more water and will essentially Chase moisture, letting them dry out and watering in a small Circle from the stock to the tips of your leafs untill the leafs have reach the pots edge then it's the whole pot each time. Feed your microbials carbohydrates and look at a root drench or tea, B1 supplements are good for root growth.
The second part is that leafs are not just solar panels and sugar factors but naturally provide two awesome things for the soil and Root zone, a shield against erosion and funneling rain water to the root tips where the earlier was mentioned. A plant roots are as wide as the plant itself, You can use this visual to understand how big your roots are for water at any stage.
I'll touch a little on Photo's and talk about up potting.
I start all of my seeds the same way, A shot glass with plan water in a warm, dark spot, 1 to 2 days till they Crack. I have per-rehydrate Jiffy punks with cal/mag and a seedling/cloning supplement for the seeds they are put into that same warm spot after adding the seed till the plants have come up, add low light, let them produced a set of Leafs and can even be pushing roots out the pucks, jiffy pucks can dry out to! Autos go right to there forever home and given kelp, a couple drops of super thrive and calmag for the first feeding then the above water practice to promote root stretching. Photo get up potted jiffy to 4" to a half gallon to the 5 gallon fabic home, when you let the plant find its boundaries it will start vegetation growth, take that a way quickly and the roots explode into new territory. I can be in a five gallon pot in 20 days from sprout for perspective. For Autos I have found that there is to big of a risk for transplant shock in their short life to suggest it being helpful especially for new Grower's that are nervous about transplanting.
The first 20 days of any cannibas plants life is crucial for whatever tricks and tips you can hit them with regarding root growth.