I'll give it a shot although i'm also new to steem.

When you Resteem a post it'll pin it to your blog, as i understand it it doesn't itself reward you with anything but you might get rewarded as a curator since, if you upvoted it and have followers, it'll get more traction.
Additionally having an interesting blog page might get you new followers.

Now for power ups, the specifics are not clear to me yet but you can convert steem coins (not steem dollars) into power up which will give you more traction on your posts and comments. Maybe like a volume knob for your posts if that makes sense.

Again i'm new so the information i provided might be incorrect

hope this helps