title: Enabling guides to help center in Inkscape
body: <p>I'm starting to learn to use Inkscape, and I'm going through <a href="http://www.libregraphicsworld.org/articles.php?article_id=7" rel="noreferrer">this tutorial</a> on creating a shiny clockface.</p>
  
  <p>Each hour position is represented by a circle, so I want to place the circle's rotation cross mark is the absolute center of the circle, as well as put the circle at one of the 12/3/6/9 o'clock positions, as in this picture:
  <img src="https://i.stack.imgur.com/FMEWn.png" alt="alt text"></p>
  
  <p>I can't figure out how to enable guides (the blue horizontal and vertical lines in the pic) to help me center and snap everything into the correct place, though.</p>
  
  <p>Any ideas? (I'm using the latest version of Inkscape on Mac OS X.)</p>