Newbie question - how to get started with graphics?

I have a single screen app with labels etc but I want to add a few lines/graphics to make it clearer. How do I start?

I've added a UIView to the interface (seems to be what is needed) and have a class based on UIView that overrides the draw command. But how does the overridden draw command get linked to the myuiview added as an outlet in the designer?

I'm clearly missing something - is there a walkthough anywhere - everything I've found just talks about overiding the draw method - which isn't helping.

Thanks