Line brushing/combing is easy, makes a big difference and gets down to the skin, I hope I can explain it properly. First though, when I consulted with my Breeder about it, she said the Furminator tends to break the guard hairs, and suggested I not use it, as judges would notice.
Line brushing is when you push the hair away from you with your left hand and rake the hair below it with the right and work your way from tail to head and from the back of one side again starting with tail to head, then the other side. Imagine making a part with your left hand, and raking with your right. When you push the hair with your left hand, you see the skin and rake with the right, going along in a smooth motion from the skin to the top guard hair. This way you get the dead hair deep down in the wooly part right next to the skin, so new hair can get the air it needs to breath. Am I making sense? It helps to see it done! I'll try and explain it better if it's not clear