How do I create a bulk edit for a product category with a specific manufa?

Hi,

Go in the menu System>Mass actions and create a mass action with:
- the data type "product"
- a filter "category columns" on the "category_id" column being equal to the id of the category you want to target
- a filter "product columns" on the "product_manufacturer_id" column being equal to the id of the brand you want to target
- an action "update the values" with what you want to change.
Once you click on the "process" button, it will run the mass action on all the targeted products.
More information on mass actions here:
www.hikashop.com/support/documentation/167-massaction-form.html