Yo JoeFish! Great results for unamended soil bud! Others have covered pretty much every base regarding what you can add, so I will chime in with other info that might be of use:
It's your first garden. Understand you're unlikely to grow prize winning produce your first season. Also understand that so long as you're planting in good sunlight and keep things adequately watered you should see acceptable yields even without gigs of data to figure out every little thing. This is NATURE after all
This first year you'll be learning quite a lot.
Plant things you already love to eat. Cukes, tomatoes, peppers (of course!). I planted ground cherries when we first moved in to our new house because I was always interested in them. Discovered shortly thereafter that they tasted, well, unique. Uniquely BAD. The damn things took over one of my raised beds and self seeded all over the backyard.
When I get home from work each day, I wash up and head directly out to walk the beds of our garden. This not only helps me relax from the day but it also gives me a chance to thoroughly check all the beds, note what needs weeding, or what might be getting et by critters, check fences and guestimate the days till the green fruits will be ripe and ready!
Read up on square foot gardening, companion planting and crop rotation. Things you plant this year should not go into the same spots next year.
30 x 30 is a great size to start! Given good management and conditions there's no reason you can't grow enough produce to take a significant bite out of your monthly grocery bill all summer long. Not only that but also enough to start canning, drying and preserving. <-- this especially opens up a whole new truly cool world.
Beware pests - rabbits and deer, creepies and crawlies, molds and blights. When the first signs are noticed take action - hoping it will go away or get better on its own puts your crops in peril. I control rabbits (they are bad out by me) with home depot chicken wire to good effect. Doesn't look pleasant to the eye but its effective.
I started in containers on the fire escape behind my apartment in Chicago about ten years ago (tomatoes). Next year I'll have 25+ types of peppers, 15+ types of tomatoes, 3-4 different cukes and beans and melons and squash and corn and eggplant and and and.... All in 4raised beds I built and hauled the dirt to fill with. (heavy clay soil) Gardening has made a hugely positive impact on my life and I wish you the same. Good luck!