I'm also a newbie. But basically what I've learned so far is that you just act normal like you would act in any other public space. There is no strict rule that you have to declare source of every image you post. What you could run on is that some bot made by a whale downvote your posts or blacklist you. You would get that for pornography, hate speech and things like that. Normal posts, memes and similar stuff are acceptable. If you make a good post with good quality somebody will pick it up, resteem and upvote. Steem is decentralized blockchain so there is no central censorship authority. The community decides what is good and what is not. Same as if you are in a restaurant full of people or on a public square. Also, you can't do much with delegated SP which you get when you register. So, if you want some exposure you have to buy some #STEEM and POWER UP.