Take a look at this post. It reach the most trending post the day it was posted. It explains the very most important part of Steem, it's pretty easy to understand, pretty fun read, (super fun read if you ask me) and that's pretty much the place where you should start. The next one should but the post which followed that one. It also reach most trending post.
https://steemit.com/steem/@teamsteem/steem-an-in-depth-overview