Whether or not you need to use agent tables depends on whether or not your MO problem has agent constraints (i.e. you have personal agents assigned to one or more account, and those agents have a finite number of hours and each offer that's responded to will consume a specific portion of those hours).
Page 24 of the MO 6.5 Administration Guide describes the property for indicating the location of agent tables in your environment, and page 228 of the MO 6.5 User's Guide (Appendix 2, "Agent Constraints") discusses those constraints in general, including a number of links to various places elsewhere in that document that describe the functionality and how to use it.
The two things that I actually didn't see in that documentation were:
a) the information map change that is required, which consists of simply flagging the agent key in your information map with the "UseInOptimization" custom property (with a value of "Subject_ID_<your subject>") and
b) the creation of a communication using the "Agent" channel.