ESPHome Code Assistance

Hi,

I need some code assistance please.
I am looking to turn a PCF8574 on and off (linked to a light).
It runs off a D1Mini and i have it displaying what i need correctly.
So far code i have.

2c:
  sda: D1
  scl: D2

display:
  - platform: lcd_pcf8574
    id: mydisplay
    dimensions: 20x4
    address: 0x27
    lambda: |-
      it.print(8, 0, "Study");
      it.printf(0, 1, "Temp:     %.1f", id(tempoffice).state);
      it.printf(0, 2, "Humidity: %.0f", id(temphumidity).state);

sensor:
  - platform: homeassistant
    id: tempoffice
    name: tempoffice
    entity_id: sensor.joe_s_office_temperature_2
    internal: true
  - platform: homeassistant
    id: temphumidity
    name: temphumidity
    entity_id: sensor.joe_s_office_humidity
    internal: true

So above works flawlessly.

I just need help if possible writing the second part of the code for ESPHome.
Below is the suggested for movement based sensor.
i just need it to turn on when my desk light is on and off when it is off. My coding is frightful.
TIA

display:
  - platform: lcd_pcf8574
    id: mydisplay
    # ...

binary_sensor:
  - platform: gpio
    # ...
    on_press:
      then:
        - binary_sensor.template.publish:
            id: backlight
            state: ON
        - binary_sensor.template.publish:
            id: backlight
            state: OFF
  - platform: template
    id: backlight
    filters:
      - delayed_off: 90s
    on_press:
      then:
        - lambda: |-
            id(mydisplay).backlight();
    on_release:
      then:
        - lambda: |-
            id(mydisplay).no_backlight();