I want to add to my shop filters like this:

Monitors
filters in this category
  • BRAND -- samsung, apple, benq
  • TYPE -- lcd, crt
  • RESPONSE TIME -- 2, 3, 4
  • VIEWABLE SIZE -- 20'', 19'', 17''

HDD
filters in this category
  • BRAND -- Seagate, Maxtor, Western Digital
  • INTERFACE -- IDE, SATA
  • CACHE SIZE -- 8MB, 16MB
  • CAPACITY -- 200GB, 120GB, 100GB, 80GB
Now I have only the BRAND filter
How can I add other filters to my categories?