Greetings! I think you have come to a good place but you will need to do some homework. In a sense, it is sort of like a construction project to get what you need or want for a grow room (or rooms).
When I started, it was with a small 4x2x5ft. high box. Now I have 3 of them. they give me plenty of quantity with 2 grows per year to give me more than enough to smoke.
So, like stated above, decide where - and how much grow area you need and want. Then I would start with potting soil (like fox farm or roots organics or organic soil with a history of pot growing). But thats just me. It gives you wiggle room to make minor mistakes and learn by them and it is easy to move grow pots around and or isolate them if need be. And what size pots to accommodate the soil. 6 plants in a 4x4 area works for me and any number of plants in that area gives me a good yield.
I would start with a tent these days. Light is most important. I would go with good quality LEDs that are designed for pot. Then figure out how much light or wattage you need to cover your grow area.
This is assuming that you are gonna grow inside..........
And read. And follow at least this forum for a while. Check out the grow journal section. Put a plan together before you buy it. dont get "Burple" lights . They can work but draw too much electricity.
It can be as complicated or as simple as it needs to be. Be careful of making too much of a science with it when you start or it will overwhelm you. Get a marijuana growers guide and read it, even if it is older than I am (and I am really old)............
Experience will be your best friend but you can start here or somewhere like it and do just fine.
thats my 2 bits - welcome to the insanity
used potting soil goes to a compost pile in my back yard for gardening and lawn growing.......... It helps break down the clay soil you know just by adding the organic matter. I had a hard time finding coco at the local hardware store.............