Associations allow you to define how two SmartObjects are related. You can configure associations between two SmartObjects and between workflows and SmartObjects. You can use associations to create drop-down menus, lookup controls, show properties of the associated SmartObject in list views, and use the associated SmartObject properties from the context browser in control values, expressions, rules, and more.

Click Add to launch the wizard to add a new association.

See the following resources for more information: