I don't have a Civic, but...
Usually the IACV is on the back side of the intake manifold, looks like a little motor.
Usually the FITV is on the bottom of the throttle body, has a coolant hose.

P28 doesn't say which OBD it is. There's probably P28s that existed for OBD-1 & OBD-2 depending on what year the P28 is made for.