To create a relationship between your entities, take the following steps:
In the Entities list, select the entity for which you want to add a relationship.
Select Manage Entity.
In the Local fields section, select Add field and provide a Display name and a Name. Select Relationship from the Type dropdown. The Advanced options panel opens.
Select the entity for which you want to create a relationship from the Related Entity dropdown list.
Select the display field to be shown in the user interface from the Related Entity Display Field dropdown list.
Select Apply.
The relationship is added as a new field in the Local fields section.
When adding data you can select values from the related entity.