Hello and WELCOME!
You simply cannot do enough research BEFORE your puppy arrives. Read books: The Perfect Puppy by Gwen Bailey and/or Puppy School by Gwen Bailery - absolute terrific, simple, easy reads, but soooooo helpful!
Easily available from Amazon.
Keep checking this site each day and it's amazing what you will pick up. But honestly, until you get that little scrap of fur under your own roof, there's nothing that can really prepare you for puppy ownership! Get plenty of sleep now - make the most of it, I kid you not!!
The breeder should give you food for at least 4 weeks, so don't worry too much about diet to begin with.
That will come in time. Just make sure you have a routine in your own mind and do keep to routine and always, always be consistent. Puppies need to know that the goal posts are set in stone. Food bowls, lots of newspapers, bedding, old towels for muddy paws (oh yes), training treats, little soft brush for grooming. I'm sure there's loads more, but that's all I can think of now.
If your puppy is coming into a family environment, do talk to the family and make sure everyone treats the puppy the same. If you don't want him/her on the sofa, it's no good your OH letting it jump up there - or vice versa. So talk now about some ground rules about how you wish to raise your puppy, so that everyone is singing from the same hymn sheet when pup finally joins you!
Lots of excitement for you, I have no doubt. It's a wonderful time of anticipation - but also a time of 8 hours glorious sleep!!!!
Love
Kay