[header] How to monitor newborn kitten growth [title] Give the kittens a warm bed. [step] During the first two weeks of their lives, kittens are helpless: their eyes will still be shut, and they should spend about 90% of their time sleeping and eating. As long as the mother cat is feeding the kittens, your involvement will be minimal. 
The kittens' main source of warmth will be their mother. You can, however, line the box or cat carrier with a towel which can be soiled and washed.