title: git checkout for xcode
body: <p>So I've been watching some videos from the Facebook Mobile DevCon 2013 (<a href="http://www.youtube.com/watch?v=mLuaUtbGvEM" rel="nofollow">http://www.youtube.com/watch?v=mLuaUtbGvEM</a>) on youtube and every time someone explains something new he or she does a new checkout and all the new code was added to your project. So is this something like different versions of your project? How does this exactly work?</p>
  
  <p>Can someone just explain roughly what a git checkout is and what is needed to set one up?</p>
  
  <p><strong>EDIT</strong>
  The speaker does a git checkout on 38:49</p>