TopLineDesigner
Online Help 

TopLine Designer is an add-on product for ACT! by Sage Windows or Web that gives you the ability to add new custom
sub-entities and it provides a framework for designing screens, relationships, list views and calculations for those
sub-entities. TopLine Designer has an Import Module. A sub-entity is another word for a sub-table.
It is a table that must be related to a specific Contact, Company, Group or Opportunity.
Entities such as Contacts, Companies, Groups or Opportunities are called Top-Level Entities.
Top-Level Entities cannot be created using this tool.

This helpful guide will walk you through TopLine Designer's two major components,  Administration and  End User.