There are many ways to skin a cat... everyone has their own favourite way to so it.
But since you asked I'll tell you what I think would be best for a first time grow.
Id suggest you use a basic peat/perlite blend. "Plants and pots premium" brand potting soil is a good brand you should be able to find easily at lowes, and it's pretty cheap and sterile. Plus it has worn castings as a bonus. I'll post a pic below.
Then I would keep it really simple and use a one part nutrient. I'm a big fan of floranova grow, its foolproof easy and works good enough that I'm using it, and I've used a lot of different nutes.
let the seedling grow without food for a couple weeks then give it 1/4 strength feed. From there you can alternate half strength feedings and plain water feedings. When I say half strength, use half the strength of the recommended rates on the bottle for the stage of plant growth. Autos need less food.
Dont prune it or manipulate it. You can bend branches out to gather more light if necessary but autos need to grow with little stress to do well.
good luck.
