I might be a little wrong because I dont have one in front of me, but try this:
Connect the Generator of a spectrum analyzer to the connector all the way to the right. Connect a dummy load to the connector on the bottom left. Connect the detector to the connector all the way to the left. You should see a dip where the port is currently tuned. Try moving the adjustment screw next to the port with the dummy load on it. Outwards should increse the frequency. Note how far up it will come. Then "Rotate" the connectors so that dummy load is all the way left, detector all the way right and generator bottom left. Tune next capacitor and repeat. Then you can do basically the same for the next stage. Check this sheet out: http://www.repeater-builder.com/db/pdfs/db-dual-junction-tunable-isolators-field-tuning-instructions.pdf
