I think you basically want to implement all the Browse and Shop pages in ATG application from Endeca.
Couple of steps to follow
1. Create an Endeca Application using DeploymentTemplatePCI
2. Configure your product-sku-output-config.xml to add the required record attributes and dimensions that you would need apart from category and item type dimensions which are provided to you OOTB
3. Perform the baseline update from ATG using ProductCatalogSimpleIndexingAdmin component and check for the indexed records using the Endeca JSP Reference application
4. Create the category and sub-category pages in using Endeca Experience Manager in Work Bench (Eg: /pages/browse, you can show different content to each category by configuring the location)
5. Invoke the page from ATG using InvokeAssemblerDroplet or using the AssemblerPipelineServlet defined in your request handling pipeline.