Absolute hygiene is important when preparing the milk. The puppies are still too small to have a sufficient immune system.
It is important to prepare the milk at about 50°C, as it cools down during preparation. When it is fed, it should always be at body temperature. If the milk is too cold, the puppy has to expend energy to warm it up in its body, if it is too hot, it can injure mucous membranes.
The packaging indicates to mix one part powder with two parts water. If your puppy has problems with digestion, you should increase the liquid concentration.