Data_template for set_cover_position - request for simple solution

Hello Clever People,
I am struggling to understand why the following automation is throwing an error:

- alias: "Velux opens when temp high"
    - platform: numeric_state
      entity_id: sensor.2f_landing_temp
      above: 25
    - condition: state
      entity_id: input_boolean.big_v_auto_setting
      state: 'on'     
    - service: cover.set_cover_position
        entity_id: cover.big_velux
        position: '{{ states('input_number.velux_open_setting') | int}}'

When I put an integer into position eg position: 50, the automation works fine.
And ‘states(‘input_number.velux_open_setting’) | int}}’ works fine when plugged into Developer Tools/Template.

The error I get when I press the “Check Configuration” button is:

Error loading /config/configuration.yaml: while parsing a block mapping
  in "/config/automations/velux_automations.yaml", line 64, column 9
expected <block end>, but found '<scalar>'
  in "/config/automations/velux_automations.yaml", line 65, column 31

line 64 is: entity_id: cover.big_velux

No doubt I am having an idiot moment. All help gratefully accepted.
Incidentally, is there a guide to what the error messages mean - for example what does and mean?

You are using single quotes for your entire template. You need to use different quotes because the system see it as:

position: '{{ states('

So you need change it to:

position: '{{ states("input_number.velux_open_setting") | int}}'

I’m not sure why it didn’t error in the developer tab.

Thanks @walrus_parka for the very prompt reply and for pointing out my tyro error.
There wasn’t an error in the developers tab because I had not thought to use the ’ at the start and the end of the template. I will do that in future to remind myself of the need to use " when I am using '.
Thanks again,