How do I start?
My pictures for the background, etc. I have.
Do you have to use Joomla? I used it when I started at my education but than I found Wordpress and was enlighted!
Not a fan of Joomla either, but the site you’ve linked to has a Beginner’s Tutorial page which gives you a step-by-step guide on how to build a Joomla site: http://www.buildajoomlawebsite.com/joomla-tutorial/joomla-beginner/
I’d also suggest Wordpress over joomla as it has a much smaller learning curve.