There are three different web parts within List Rollup and each are configured a little differently.
Overview of the List Rollup Classic Configuration Options
For List Rollup version 6.0, Bamboo List Rollup Classic Edition has been retired so Bamboo provides a new option to integrate List Rollup Classic Edition into the List Rollup Schema; this option is known as the Bamboo Aggregation Service.
To start creating a new List Rollup Schema, add List Rollup Schema Designer web part to a page and click the New Schema button in the Web Part toolbar.
A new section called Aggregation Service is now shown; it will define which aggregation service the Schema rollup will use: select Bamboo Aggregation Service or SharePoint Aggregation Service you want to work. See Select the Included Lists for your Schema-based List Rollup
Overview of the List Rollup Grid View Configuration Options
Overview of the List Rollup Schema Designer Configuration Options