• To select an entity: double-click on it; its color will change from green to orange.
   
• You can also select relationships between entities, only this relationship will be used to link the two entities. To do so, double-click on the relationship; the link will appear in "bold".
   
• You can also choose to exclude entities. It only makes sense if your strategy allows unselected entities to be used.
  To exclude an entity, use the popup menu (right click) and choose the Exclude/Include item.
  (In the screenshot, Pathway has been excluded).

Note: By selecting a relationship you will automatically select the related entities.