Search for the group of contacts you want to add to a particular category or categories by using the Quick Search or Advanced Search.
By doing this, you will return all the contacts you want to add to a particular category.
Remember, to perform a function on a contact/or group of contacts, you must first "search" for the contact/s. Then, once you have retrieved the group of contacts to the contacts form, you can perform the action on that group of contacts.
Your search will return all the contacts that matched your search criteria to the contacts form.
Now, simply click on the "Add Contacts To Category" button.
A new form will pop-up. Just select the category you want to add contacts to and click Add.
USING the buttons BELOW the contact record box, will add all the current contacts returned by your search into the contacts form to the category you selected. If the contact is already in the category, it will skip over the contact and the contacts category data will be intact.