A Newbie question about the market place

I have a little bit of steem dollars I'd like to eventually like to convert to steem power.

Best I can tell the most efficient way to do this is to trade the "sbd" for steem on the market then power up.

I just don't understand the way the market works am I just putting an offer out? And how do I use the stats at the top to make a fair offer?

Thanks for any help