When creating your character, you receive a free Racial Aspect. This functions exactly the same as any other Aspect. The Racial Aspect is likely going to overlap with your other main Aspects.
Half races will have one Race they associate themselves with more than another, and this race defines the Racial Aspect. For example, if you are a half-elf that was brought up by humans, your Racial Aspect will be the exact same as a Human's.