What should be input and output for CA3020A power amp circuit and how to implement it?
An archaeological dig through data books came up with RCA Victor Co.; RCA linear integrated circuits 1967.
Single-supply range is from +3 to +9V DC.
Absolute maximum voltage for the differential amplifier (I take it this is pin 11) is +12V DC.
Absolute maximum voltage for output stage, peak-to-peak is 20V
maximum input voltage (single-ended) is +/- 3V p-p 
About &quot;class-B&quot; output. This amplifier is really crude - when they say &quot;class-B&quot;, they mean that there is no provision whatsoever to reduce cross-over distortion. Both circuits 1(b) and fig 8 have this problem. You should re-consider using this chip in audio applications for this reason.
Figure 1(b) circuit is similar to one in this reference book, with the exception of the 1k DC bias resistor attached to pin(11), which is missing (infinite resistance) in the reference circuit. What is maddening, is that audio transformer turns ratio is not given. However, the reference circuit does give Vcc1, Vcc2: both +9V DC:

3.3% distortion (@ 135mW power out)
Idling current is given as 22mA.
Input resistance is given as 50k ohms
Input voltage for full-power output: 44mV
Maximum audio output power: 545mW

For figure 8, a reference circuit with 65 ohm load resistors is given, instead of 50 ohms in OP's circuit. This gives slightly more gain \${e_{out}} \over {e_{in}} \$ of 44 dB.
Once again - this ancient circuit is flawed; suitable only for nostalgic reasons -  otherwise, use something more modern.