Welcome on board :) You don't need to worry too much about bitcoin unless you want to start converting the steem to your local currency very soon or you decide you want to start trading cryptocurrency (which could happen, some of the people I followed went from knowing nothing about cryptocurrency to becoming traders!).

Resteeming is resharing/reblogging, so if you find something you like you can "resteem" it and then anyone that's following you will see it as well, and possibly discover some more things that they like :)

Have fun!