CatherineSarah, the BLV link that Island Monkey gave leads to the BLV's online tool. Plug in your variables - age of dog, dog's country of origin, your status - and it will tell you exactly what you need to enter Switzerland. Here's the direct link:
https://www.blv.admin.ch/blv/en/home...tchen.html#par
Your next step will be AMICUS registration, mandatory in Switzerland. You will need a vet to initiate the process, and it has to be done within 10 days of arrival. So if you don't already have a vet, look for recommendations from local dog owners, or post a question here.
https://www.amicus.ch/Account/Login
You will then also need to register your dog with your Gemeinde. See your Gemeinde website for details as to the process. In my Gemeinde one needs to present proof of liability insurance to register - but I understand that is not the case everywhere.
An obvious thing, but nonetheless:
Will you have an extended time with the pup in the UK before flying over? If not, please ask the breeder to start acclimating the pup to a travel crate as soon as is age-appropriate, well before you fly. Crated travel, even if in cabin with you, can be stressful. The more acclimation training the pup has before the big day the better. Also ask the breeder for something with the pup's mother's smell on it - a fleece, etc - to put in the crate.
And my usual comment: Have you found a Welpenförderung class yet? (Yes I know these are not required, but highly recommended. I urge all new puppy owners to take Welpenförderung classes, it's a key socialization step, especially in these pandemic times as we are social distancing.) Dog schools are open with COVID space restrictions - so if you have not booked classes yet, it would be a good idea to do so.
ETA:
Forgot to add the most important comment:
Congratulations on your new addition, may the journey be easy on both of you - and here's to a many happy adventures together!
Oh, and when the little one arrives... we all love puppy pictures.