I've found the best approach is to make it task-oriented.
Download xCode.
Come up with a simple concept app (stopwatch or alarm clock, for instance), and search out on google examples and tutorials that already do these apps. Figure out how to download them and run them on the simulator.
99.99% of every question you'll ever have about specific things have already been asked and answered; when you develop these inevitable questions, search them out.
Once you get your first app out, try either adding bells and whistles or coming up with new apps.
