Well, since we are on the MMM forums, I would suggest don't buy anything at first, since this is new to you. Then, see what gets uncomfortable as you ride, and buy to fix that. Likely you'll want to avoid a seam in the seat for longer rides, so bike shorts might be in order.
I ride with electric assist, so wind resistance doesn't matter to me, but on your own power that is very important at higher speed. That's why so many wear all that lycra stuff.
Personally, my North Face 'hydrenalite' jacket is my go-to three-season wear (not summer, too hot). Breathes to let sweat out, blocks wind really well, and is essentially waterproof (in theory water eventually gets in, but I have never experienced that). Not cheap, but is still like new after about 10 years. Just add other layers under it depending on temperature.
Not clothing, but I recommend you get good lights and always have them on (at least red flashers on the back). An LED light kit can be had for ~$15 and will last for many hours (at least 10ish) on rechargeable batteries. You really want to make sure cars know you are there.