1985 Toyota Supra fuel pressure check

Where do I hook up a fuel pressure gauge to a 85 supra? I assumed if I removed the bolt going to the top of the fuel filter, banjo bolt, I could read the fuel pressure from there. When I started the car, it read 0. When I loosened the bolt going just slightly, it squirted out fuel. So obviously it has pressure there, why did it not read anything on the gauge? The book says to, remove banjo bolt and detach cold start fuel pressure gauge to the fuel rail. I do not see where they are talking about.