Hello, this account is to maintain Edward Vance and associates articles This user, in accordance with the Wikimedia Foundation's Terms of Use, discloses that they have been paid by Edward Vance for their contributions to Edward Vance, EV&A Architects.
If the sub-category page does not already exist, then you have to create it first (see the tip How to create a category). For example, after you create the Category:Apes by common name page, then you click edit and add [[Category:Animals by common name]] to the bottom of it.