I needed to add the code into Doc-head-core.liquid, but you might need to add the code somewhere else, like theme.liquid This is the top of my theme.liquid - and this line ( {%- render 'doc-head-core' -%} )  is how I knew I needed to change doc-head-...

no, not in there. Step 1. You need to check the name of that collection file in the template folder. What ever that name is, will be the name you put in the code.  if the file name is list-collections.json, then the line should be {% if template == '...

In your templates folder you will have a file something like list-collections.json    Do you have that ?  Could be collection-list ?  It can be different for different themes.   What ever that file is called thats what you should put in this part:  {...

Hi! Try changing the second line of your code to the below which is in bold. Kind regards, Brooke  {%- if page_description -%}{% if template == 'list-collections' %}<meta name="description" content="whatever you want to put in here ">{% else %}<meta ...

Check you file:  doc-head-core.liquid and you can try updating the code there ( using the above code from Jondiego ) 

Thanks this code worked perfectly for me. Though I had to put it in the file:   doc-head-core.liquid: