How do we make an entity in Home Assistant from two other entities?

// https://youtu.be/QheN8Jz8vTY
//
sensor:
  - platform: template
    sensors:
      difference_power_entities:
        friendly_name: "Consum Casă"
        unit_of_measurement: "W"
        value_template: "{{ (states('sensor.inverter_active_power') | float - states('sensor.power_meter_active_power') | float) | abs }}"