The catalog and RPD get built when you install ... You will get the full complement of modules - then you can trim out the ones you are not licensed to be using.

How are these joined in the RPD? you are better off following Oracle's example (from the RPD) and since you purchased apps you have that RPD and all you need to answer the question. 

Did you follow the implementation/configuration guide yet? or are you at the initial installation? The newer versions of the Apps use ODI as the ETL/ELT tool, but the foundation is the same. Here's a link to the Apps documentation library: Oracle Business Intelligence Applications Documentation

Are you implementing Oracle BI Apps or Oracle Transactional BI, or Oracle BI Fusion edition? usually the install/config process depending on options you choose will build the RPD (business model) and the web catalog (reports and dashboards) and put them in the OBIEE default locations for both.

You need to follow the configuration guide for the version of BI Apps (and specifically for the modules you've implemented)

_A means aggregate table ... did you map the domains and group accounts correctly in BIACM?

Try not to go resurrecting dead (abandoned) threads ...

OBIEE - (Row-wise|List of Values) server variable [Gerardnico]