[Pharo-project] Spec documentation and examples

Hi: I'm starting to develop with pharo using spec. I really like the spec approach. I already review some examples that come with spec but I only get UIs with a bad aspect by following the examples. I would like to find more documentation and examples about how to write the defaultSpec. Documentation about how to use the spec structure to develop a nice and usable UI. Thanks in advance, Daniela Meneses