I don't quite get what you're not able to do. OBIEE can run DB queries with Direct Database Request against a whole bunch of databases. Are you not able to do this, or expose the information you want through a database query?
I am probably not being clear as I am new to OBIEE, been an EBS developer for over a decade.
I have created a connection to the OLTP system and I am able to run queries. Those queries can be used as a data source for a report. I would like to know how to use the production OLTP system to run dashboards against. I want it to be able to run frequently and I could simply bring it up to monitor the health of our systems.
I thought this might be a quick win where I could learn more about the system that I am going to be put in charge of.
Pretty sure Direct Database Request is what you're asking: http://gerardnico.com/wiki/dat/obiee/direct_database_request#g1
This is a way of avoiding the RPD (through which queries would usually be generated having modelled the data first), except for the required connection details down to the source.
When you say "I have created a connection to the OLTP system and I am able to run queries. "-- what do you mean - is this in OBIEE you've created the connection? if you can run queries, what is it you're asking for help with? ...