Syncing Sub Categories To Main Categories Through Csv Product Import

Hi there

I am quite new to the platform so please excuse my ignorance. I am trying to do a CSV upload and I have come across some teething issues.

In my CSV I have a column for Main Category and one for secondary category. When I complete the import my secondary categories are not syncing. I can only sync to the main category. Does anyone know how to sync it directly through CSV import.

For example, on the CSV sheet I have main category as "Cards & Stationery" and sub-category as "Books". But nothing is updating under the Books sub-category.

Please see the attached images.

I am not sure what I am doing wrong.

Really appreciate your help!



CSV screenshot

Just make an export of one product with secondary categories to see required format. I think, wrong format causes the issue