Biewer terriers coat should be silky. Silky coat feels slippery and cool to the hand. The coat has no undercoat. Taking care of a full grown coat is demanding and the coat has to be taken care regulary. This means at least weekly washing, brushing and detangeling daily. Show dog's coat needs to be wrapped to achieve the beautiful look and to grow. Wrapping the coat also prevents it's breaking. Taking care of the coat is very demanging especially in ages 9-36 months. The dog can wear "wrapping suit" to protect the wraps.
Home dog's coat is recommend to be trimmed short. Look for a groomer, it's good if they have experience of grooming a yorkshire terrier. It's important that the grooming suits to the breed and brings up the breed standard alike features. If not groomed correctly, biewer can look like a whole different breed.
Puppies should be introduced to grooming at a very small age. Washing and brushing is learned regulary, so the puppy gets used to it. You can also pluck the hairs inside the ears with fingers to help the ear canal air out. The hairs at the top of the ears are trimmed off (both sides) so the ears lighten up and gets to the right positions. Too long and heavy hairs at the ears can leave the ears folded, even though usually the reason for folded ears it's too weak or wrong structure of the ears.
You should pay attention to high quality products and the products that the breeder recommens. Usually the best products for your dog is found by trying many different brands and products.