Welcome to Steemit @vonyugen! I recognize you from Minds. Don't sweat it man, it takes a little time, but the longer you use Steemit, the better you understand it, and the better it gets. I actually prefer Steemit to Minds, myself. It's an amazing platform, but it's different than Minds or FB. There aren't really any RULES, but the community at large has some pet peeves that we try to keep to a minimum. Like @boyanpro said, Steemit doesn't make or enforce these "rules", the community does. the main ones are:
Spam posting. That's sort of built in. You have a certain number of resource credits depending on the amount of Steem Power you have. If you post to much, you'll have to wait on your RCs to recharge. You can check all that here. If that's not enough and you would like to post /comment / upvote more, You can buy some Steem (cryptocurrency) and power it up. This gives you more total RCs and makes your upvote worth more. Now is a good time while Steem is down. $0.78, at the moment. You won't lose that money. Anything you power up can be powered back down over the course of three months into the liquid cryptocurrency.
nsfw. tag Porn, nudity, anything you wouldn't want your kids seeing or reading that doesn't have the "nsfw" tag as the first tag on the post, will be flagged, and hurt your reputation score.
Plagiarism. Copping someone else's work and claiming it as your own. If you quote somebody, use pictures, videos, etc. It's understood that you're not always going to know who it belongs to. Especially when it comes to memes. Just do your best to give credit where possible if it isn't your work. In the case of the pictures you posted, I would think that simply stating that you are unsure who took the pictures, would be sufficient in that case. Mentioning at the bottom that you own the rights to the pictures you've bought that you used in the post. In short, give credit where you can, and if you don't know, just say so.
Look forward to reading your articles! @rushofwaves is here too. If you havn't already, check out Steempeak. It's just a better user interface for Steemit. If you're into card games, SteemMonsters Is crazy fun!
Hope that helped answer you're questions. Let me know if you need any help with anything else!