Back linking simply refers to linking, nothing more!
You might have been confused by the term backlink. If you create a link back to your hub, its a backlink. POst the URL of your hub in Facebook, its a backlink.
As you asked this question, a link saying "sholland10" is visible after asked by, this is a back link.
Some popular websites where you can create great backlinks:
If you answer more questions, or become active in forums and comment in other hubs, that is also a back link.