The anode is the bottom side of the diode in my receiver. Make sure it is really ground or you may send RF into who knows where. You can either connect this to a rear-panel jack. Or, you can run this output directly to a metering circuit. AGC Output Output is a negative voltage for no signal.
Output is a positive voltage when a signal is present, increasing with signal strength.
A 1 Volt full scale panel meter might make a good signal meter. A 1 Volt meter of some sort. The resistor is whatever value you need to take the meter off of the peg. The transistor is whatever you have in the junk drawer, carpet, stuck to the bottom of your shoe, etc. The meter can be anything that resembles a signal meter.