Need template for mqtt button with json formatting

i want to publish a "1"over MQTT with json formatting but cant find the right syntax. anyone done this before?

obviously this is terribly wrong but where i left off at. the first two work and are easy because no josn formating. the third one is where im striking out at

mqtt:
  button:
    - name: "Pico_Button_ON"
      unique_id: pico_input_ON
      command_topic: "pico/testONOFF/control"
      payload_press: 1
      #availability:
      #- topic: "pico/testONOFF/state"
      qos: 0
      retain: false
      entity_category: "config"
      #device_class: "restart"
    - name: "Pico_Button_OFF"
      unique_id: pico_input_OFF
      command_topic: "pico/testONOFF/control"
      payload_press: 0
      qos: 0
      retain: false
      entity_category: "config"
    - name: "seed_starter_light_1_ON"
      unique_id: seed_starter_light_1_ON
      command_topic: "seed_starter/status"
      payload_press: '1'
      payload_template: "{{ value_json.IN_1}}"
      qos: 0
      retain: false
      entity_category: "config"
      #topic_template: "{{ value_json.IN_1 }}"

you made a template to extract json data, you need make one to generate the payload …

like the mqtt example here: Templating - Home Assistant

hey thanks, yes, thats what im trying to do. i have looked through the MQTT page for several hours now. i dont see an example that is clear enough for me to understand so was hoping someone else has done something in a way i can learn from

ok, after lots of trial and error the solution seems straightforward but damn this leaning curve is a B.

if anyone ever wants a down and dirty button to MQTT to JSON this may help.

the key parts being the command_topic and command_template

    - name: "seed_starter_light_1_ON"
      unique_id: seed_starter_light_1_ON
      command_topic: "seed_starter/status"
      command_template: "{ 'IN_1' : {{1}} }"
      qos: 0
      retain: false
      entity_category: "config"

if it only has to send the ‘1’ i guess it will be fine, otherwise it should be:

"{ 'IN_1' : {{ value }} }"

hey thank you, so this lines up with where i was trying to go next which is to send any other data, how do i define what {{value}} is in your example?