Understanding custom headers

I’m designing a theme to allow custom headers. I’ve got the default image and the ‘set your own image’ working.

Now I want to enable the functionality for turning header text on/off and setting the colour. I’m guessing I just need to use some magic CSS class to wrap the text, or some such, but I can’t find documentation about it.

Since it matters for some path issues, I’m working in a child theme (with Sandbox as the parent.)

I apologize if this has been well covered somewhere – when I try to use the search above it’s searching the whole WWW, not just the forums.