Hi
I've recently got a Miniature Dachshund puppy. She is twelve weeks old. I'm wondering how much to feed her as she does not eat all of the food as recommended by guidelines on the food packaging

How much was the breeder feeding her?
They should have given you a detailed care sheet telling you what food to give her and how much.

What are you currently feeding and is it the same as her diet at the breeders?

At 12 weeks I would say she should be eating about 1/2 - 3/4 cup of dry food daily.

It is recommended to break this up into 2 or 3 meals.