Pretty general information, so basically you get sitelinks listed if Google can easily identify that some pages are of particlular value and their visibility can make the search faster.
Google has not generated any sitelinks for your site. Sitelinks are completely automated, and we show them only if we think they'll be useful to the user. If your site's structure doesn't allow our algorithms to find good sitelinks, or we don't think that the sitelinks are relevant to the user's query, we won't show them. However, we are always working to improve how we find and display sitelinks.