does it matter which you plug? And where is the other fitting for the idle up control?
I plugged one of the fittings then hooked one end of one hose to the plugged fitting and the other end to the idle up control valve (i.e. the thingy with the white screw adjustment knob on top). Since there is only one hose, doesn't matter where its plugged, I imagine a BB pressed inside the hose would work too, but I didn't have a BB.
Simple vacuum circuit, you have one hose from a vacuum source on the intake plenum that runs to the valve on the p/s pump. The other line runs back to the idle up thingy (same place the A/C idle up VSV connects to - they both do the same thing). When there is pressure in the p/s pump, the valve opens and lets vacuum pass from the intake to the output hose, bumps up the idle.