From the other thread - the puppy is 9 weeks old. At this age it's quite, quite normal for her to not walk "nice" on leash - she's just a baby.
Be very patient and start slow, with treats
every other step; given time and patience he'll get it
Also, she should not even be on the floor in the vet's office for now - most likely she does not have all her shots yet, so please carry her.