What is the best way to go about learning Objective C?

For work, I’m designing and programming an iPhone app for our technicians in the field. I was put on the task for my design capabilities, but due to lack of resources, I am also now coding the app. I’ve never coded anything before in my life. I know some HTML and that’s not even code.
This app will be done in Objective C. I know there’s a plethora of information on the subject, but I want to know the best way to go about learning it.

The App: First version (proof of concept) needs to download and view XML files.