How does RegExp works in here? Rated 2 out of 5 stars

Cannot figure out how does RegExp works in here. It is shown in 'Content Extraction' clip yet i fail to evaluate regex i enter.

Multiple elements xpath Rated 2 out of 5 stars

The only thing is that if i want to find the xpath of multiple elements, it doesn't work, but the Scraper, Google Chrome extention, provides such a feature.