How to assign category code to asset group?

Hello everyone,

I would need clarification on how to assign category codes to asset group.

From reading the Oracle EAM docs, it suggests that the association of category code is done in EAM with transaction Setup /Category/Category Sets. There is an Assign button here. Intuitively, I would think that once we enter the correct code and click assign, then the next screen should allow to associate category code with asset group. However, this does not work work for me. The New button is greyed out.

The only way I can associate the asset group to the category code is by doing it in the item master of the asset group (Inventory module) from the tools menu of the item.