Do you want to search in all categories or in this category ?
Go into your Lists & Subscribers section in the Email Marketing and click on More -> Import. That allows you to import users via .CSV file format and map the fields to the properties in the CRM.
You can also subscribe users in bulk from your current Contacts tab by marking them and clicking on More. Then select Add Contacts To List and select to which list you want to add them. This will subscribe and add the contacts to the selected list.
