Trying to make a custom grid

I am trying to make a card with a custom grid so i can place card where i want.
I found something that would be the best for the card i am using but i can not get it to work.

i made a test code, I know the grid position numbers in the yalm are random but if i try to place a car in the grid it stays where it is.

type: custom:layout-card
layout: grid
gridrows: 75px 75px 75px
gridcols: 120px 120px 120px
cards:
  - type: entities
    entities:
      - sensor.sun_next_dusk
      - sensor.sun_next_midnight
      - sensor.sun_next_noon
  - type: entity
    entity: sensor.sun_next_dawn
    gridrow: 1 / 2
    gridcol: 1 / 2
  - type: entity
    entity: sensor.fan_speed
    gridrow: 3 / 4
    gridcol: 2 / 3
  - type: entity
    entity: sensor.itho_co2
    gridrow: 3 / 4
    gridcol: 1 / 2
  - type: entity
    entity: sensor.ithocve_humidity
    gridrow: 3 / 4
    gridcol: 1 / 2
  - type: entity
    entity: sensor.ithocve_temperature
    gridrow: 2 / 3
    gridcol: 1 / 2

I can not find much about this type of grid position, so thanks in advance.