*structure rules govern the type and content of cards in a given set. The content of every card in the set is a copy of the structure rule’s content.

You can create powerful card structures using contextual names. Suppose a structure rule for City cards nests a card named “+Country”. This establishes a pattern in which every City has a Country field.  For example, the City card “Moscow” would nest a field card named “Moscow+Country” with the content “Russia”. and the card “Berlin+Country” could contain “Germany.

Nests are easy to create and manage using the nest editor, which can be opened using the curly bracket icon ({{}}). This tool will help you create and configure nested fields, both through nest syntax options (which only apply to the fields when presented within the structure) and through rules (which apply in any context).