WordPress theme is developed with three things.
This is the most simple skeleton you have to remember for developing theme. After this you can head over to the WordPress documentation .
Apart from that you can also follow the third party theme frameworks for child theme with genesis framework . You will find the information for development of simple themes. More complex features like theme dashboard and plugins also have specific documentation.
Start from here and I am sure you'd be able to hack a theme or two in a weekend.