At passport control you can walk through to the baggage claim if you get the "show receipt at exit" receipt. If you get the X with "report to passport control" then just flag down a CBP officer. Some airports are setup better for this than others. ORD has a CBP desk after the kiosks where an officer clears you even if you don't get the X. My times at TBIT at LAX I remember thinking I'd really have to swim upstream if I got the X, but it never happened. At other airports: EWR, DFW, SFO there has been a CBP officer by the kiosks helping people use them or get to a booth if they get the X.

But again, if you don't get the X you can normally walk straight to the baggage claim area and just hand the receipt to the CBP officer at the exit of the customs hall. (Non-GE people would hand in the blue customs declaration form.)