new to this - what is no follow link?

A normal link has nothing extra. A nofollow link has rel="nofollow" in the code, which tells Google not to treat it as a vote for the site it points to. Google now calls it a hint rather than a strict rule, so it can still choose to follow it. You'll see it on blog comments, most forums and paid placements (those should really use rel="sponsored"). Still worth having some - they bring visitors and a natural link profile has a mix of both.