Welcome to the community! You will receive great help here since we all want to see you succeed.
I do indoor grows year round and did an outside grow for the first time this year but I have no experience with autos. I have a 2x4 tent and I can grow three photoperiods but it is a very tight squeeze. I’ll probably only grow two this Fall. I grow in living soil with dry amendments.
First I would recommend reading through some of the grow journals and decide what type of medium you want to grow in.
I’ll just provide you with what tools I have found valuable and the type I purchased but I am sure others will provide additional items and other products. There is no wrong way to grow in my opinion.
To start you will need:
tent - I have a cloudline 4 x 2 which will hold two photoperiod plants comfortably but IME (in my experience) three plants can be a bit tight for photoperiods - I don’t know anything about autos! Buy some “zipper grease” to lube the zippers. Also when you open or close the tent pull the zipper outwards towards you and pull slowly - I found this avoids the zipper sticking.
Pots/bags. I use 3 gallon fabric pots (also find something to put beneath them so any runoff doesn’t pool in the bottom of your tent). Also make sure to empty any standing water.
Lights - I’ll defer to the experts - don’t skimp on lights like I did! @dbrn32
Nutrients - Again I’ll defer to the experts depending on the medium you choose. I grow in living soil and use organic dry amendments. It will depend on your grow medium on what might suit you best.
Meters - pH - I use the Apera 20. TDS - cheapo yellow one off amazon. Temperature and relative humidity meter. One came with my cheapo lights.
Ventilation - I use a 4" cloudline and I wish I would have bought the 6"! I also use a carbon filter cannister when they start smelling. Cloudline has a basic model and one more sophisticated - I think the T and S models. Also a couple of clip on oscillating fans to promote air circulation in the tent.
Misc - I use a 1 gallon pump sprayer for watering. pH up and down off amazon to adjust pH or you can use citric acid and baking soda. Isopropyl alcohol and hydrogen peroxide. Stainless steel trimmers (the aluminum ones eventually rust IME). Definitely a notebook to keep track of feeding schedules etc, Start a grow journal and tag in people by using the @ followed by their username. Like @JaneQP.
The most important thing is PATIENCE!
I’ve only grown clones so I know little about sprouting seeds. @Hellraiser has some great threads to read through.
In the time it took me to respond I see you have already had a few responses.
Help is always just a question away.