How Do Steem & Steem Power Work?

Hey everyone.

I am one of the new Steem users. I am here since the first days of the November.

I don't really know how do steem and steem power works.

Can anybody have information about this topics, clear up this topic for me?

If you have the information or if you know good post/posts about this topic can you tell me?

Thank you so much!