Goto a post that you like - make sure you like it now! [I like @craig-grant for example] Scroll down to here:
Click that resteem arrow to resteem it to your timeline.
Now click the OK button. Congratulations, you have now resteemed!
Be proud of yourself that all your friends will now see this post in your timeline, then Steem on! Cool.
P.S. Also in the quick minnow series:
QUICK MINNOW GUIDE: How To 'Power Up' Your Steem Made Real Simple.