Yelling at the pup to stop barking, is like you barking as well and it increases the pups anxiety or fear. The pup is likely to think that you are joining in and will only continue to bark. There are many levels of barking some are just as simple as “did you hear that” to “go away, I’m big and threatening”.
The cause of some barking problems is similar to the cause of some excessive chewing and digging problems, not enough time spent with the puppy, and not enough exercise for the puppy.
Practice makes perfect!
Set up friends coming to your door and ringing the bell. Use the techniques above. Sit/stay or down/stay works well for this. Have treats ready so when the barking stops and a sit/stay is reinforced the dog gets a reward.
Make sure not to run to the door and tell the dog to be quiet in harsh tones or the dog will think that there is a threat on the other side of the door.
Negative reinforcement is still reinforcement so try not to get into the habit of yelling at your dog.