Look up the firing order for the engine and then click the DEFINE NEW ENGINE icon on the top toolbar.
Fill in the fields in the dialogue that opens.
For example, Acura 3.2 TL.
Engine Size: 3.2
Engine ID: 3.2
Bank Numbering: Sequential
Oxygen Sensors: 2 (really doesn't matter if he is using exhaust probe)
Spark Dist: C.O.P.
Honda 3.2 engine will now be added to the program for future use.