Twilight is a Preprocessor for Twig, so if you're familiar with Twig you'll feel right at home with Twilight. In fact, you should read through the Twig for Template Designers documentation, everything you can do there, you can do in Twilight, since it compiles to Twig syntax.
How It Works #
Twilight #
You write components and templates using the Twilight syntax. This is then compiled into valid Twig syntax. Things like directives and components are transformed into Twig expressions.
Twig #
Twig works by compiling your templates to PHP classes. You can read more about how Twig works on their Twig Internals page.