You can’t really “add the plugs to emoncms” but you can get Home Assistant to send the readings.
Note - you need to calibrate these devices as they are very inaccurate otherwise.
In HA you will see these sensors assuming the plugs you have do export power usage (not all do).
Have you installed an MQTT Broker in HA? If not - don’t and follow this. If you have installed a broker, then it’ll need a bit more fiddling.
I think probably the easiest way is to point HA to the MQTT broker on your EmonPi and use the
In your HA
configuration.yaml put this;
broker: <emonpi IP>
The values will just appear in your Inputs one Emoncms.