Google Ads - Shopify Collection / Category advice

Need some advice and instruction for integrating Shopify and google ads. We have them integrated and linked via our google merchant account so we can use shopping ads, but in google ads i am unable to target a specific collection of products from shopify - i can't see the collections/categories to target. ( i can see only the inbuilt google categories).

Need guidance so i can target specific shoppify categories in google ads.

I will screenshare using google meet so you can guide