First time gardener

So I was extremely excited to start my first garden in our backyard. I began very small so I would actually be able to take care of it. But being a novice, I forgot an important step. Luckily, I had Kade's dad to point it out to me. Last Sunday his parents came over to check out all the work we have been doing on our house (including my garden). When he looked at my beans, he knew right away I had a bug problem. I was in shock, even though it should have been obvious. The bean plants were pretty much just the stalks, no leaves. But because I didn't really know what bean plants were supposed to look like, I figured they were supposed to look like that.... Well, they're not. Not only were the beans missing their leaves, but the cantaloupe plants were completely gone. I noticed a few days before one had disappeared, but I thought maybe it died or something. But then both disappeared, so I don't have anymore cantaloupe plants. :(
But, thanks to Kade's dad I have now put some bug killer on my garden, and hopefully I'll still get some vegetables out of it this year.
I hope I'm not missing another important step...
Oh and I should comment on my flower garden. The sunflowers I had started from seed in my window seal have no grown so huge they are bigger than the bushes we planted this spring. Hopefully, the stupid thing will produce some more flowers, right now it just looks like a big green monster...
Ok I got some pictures, thankfully the sunflowers have bloomed :)
And I have a mini-green tomato! yay!!