Confusing if you are new in omega but this notes will help you.
Omega 7.x-4.2 (default theme)
A powerful HTML5 base theme framework utilizing tools like Sass, Compass, Grunt, Bower, Ruby Version Manager, Bundler and more.
4 Do list in creating subtheme:
- Installing the Omega Framework
- Using Omega tools to create a subtheme
- Understanding the layout
- Basic configuration options