How to edit product page for specific collections

Store Design
1

hi im looking for a way to bulk edit a specific collections product page, i want to add a sizing guide for specific products, for example for my nike products i would like to say that they fit true to size, is it possible for me to add a rule to my nike collection so that every nike product has this automatically added? hope this makes sense.

2

In the product page template you need to check whether a product belongs to a specific collection or not.
If found true show the size guide else do nothing.
Something like this:

{% assign CollectionHandle = 'your-collection-handle' %}
{% assign isCollection = false %}

{% for collection in product.collections %}
  {% if collection.handle == CollectionHandle %}
    {% assign isCollection = true %}
  {% endif %}
{% endfor %}

{% if isCollection %}
    
{% endif %}