How should I got pick up the puppy from the breeder? Big car and with its cage? Would I need to bring anything else with me?
I don't know if you need a big car, but definitely a crate makes things EASIER if it's just you in the car. If you have somebody with you who can hold the puppy that would be fine, but otherwise, they are all over and falling off the seat....
With Bertie I put the crate up front in the passenger seat (airbag is always turned off on that side) on the way home. That way he could see me and not be creeped or stressed out. He rode up front with me for a few weeks until he became too big for the crate.
The first crate - you want one that's spaniel sized. He needs enough room to move around and have a few toys in there with him or chews. But you mainly want him to learn to be calm and settled in the car.
I like covered crates because the first few weeks until you get all the vaccines, you will be running to the petstore or places like that while getting him used to carrides (you need to go somewhere EVERY WEEK so the car feels safe and happy to the dogs) with your puppy and leaving him in the car. I absolutely do not want people peeking in my car and seeing a golden puppy.
Also what should I do when I bring it back home?
Let him sleep when he wants to sleep. Train him to relax and sleep without you constantly touching him and being in contact with him. This will help overnight or those times when you want him to sleep without you around.
Play with him when he's awake and coming into your space for attention. And I would be sitting on the floor and encouraging him to come to you to play vs you chasing him all over to play with him. It helps later on when you are starting to train 'come'.
Always have treats in your pocket. I use bread for puppies because it's bland and you can break it apart and give tiny pieces. Puppy milkbones (very small and broken in half) work too. Any time your puppy comes running to you, you pull a treat out of your pocket and telling him 'good come'. Never get in the habit of just giving treats 'just because'. Treats should always be connected with something like puppy running to you or after they've gone potty outside. That makes the treats 'high value' and helps them learn faster.
Get started on a feeding schedule - usually 3 or 4 times a day. Keep in mind that the first few weeks, it will be food in/food out with their digestive systems. You can feed 1/2 to 3/4 cup 3 times a day to start with. Moistening the food with warm water (not hot) helps with a fussy eater.
Get used to a potty schedule. While the puppy is awake and moving around, you need to be taking him out every 10-20 minutes. Let them sleep if they are sleeping, but rush them out immediately when they wake up.
I know I should take it to the vet for check up.
Yep. Within a couple days. You need to get puppy set up at your vet. Some vets are nice enough to have complimentary exams for new patients if they are puppies. Primarily because they know you will be coming back for shots and health visits. But even if they don't - you want to get them in, set up, looked over, and get that first fecal test done to make sure he doesn't have any parasites. And you will probably get your first heartworm meds pill at the same visit. And set up your schedule for vaccinations.
*** Before you leave the breeder with your puppy, make sure you have that schedule written up and in your hand before you leave. As well as any information on worming, microchips, etc.
You need 3 rounds of the distemper/parvo shot, 2 rounds of lepto, and rabies later on.
I am waiting to get the puppy soon and I was wondering what are the essential materials that I need to buy.
Ask the breeder what kibble they've been feeding the puppies. You want to buy a 15-30lb bag of that exact kibble to feed your puppy.
You want to buy chewie things of all different textures - rubber toys, nylabones, antlers... do not really give any edible bones for a while. Probably an exception are himalyan cheese sticks. I bought those for Bertie and they were a LIFESAVER. o_O
You want rope toys - because the texture will help with their teething later on.
You want soft toys - because you have a retriever and inevitably they will want to have something soft to carry around and chew on.
You want to buy a puppy collar (nothing crazy, it will last only a month if that). And a leash.
You want a brush (pin brush or slicker) for brushing your puppy out. You won't be brushing his belly too much with the slicker, because it can scratch his bare skin. But it's important to really get your puppy used to you brushing him every day everywhere else.
You want toenail clippers or a grinder - whatever you intend to use. As this is your first puppy - have the vet show you how to trim nails. Even if you decide to always take your puppy to the vet or a groomer to have the nails done, it's important to know how to clip your own dog's nails.
You want shampoo.
And you want a big wire crate for home (a different crate than the one in your car).
And don't forget to stock up on puppy treats. Stay away from the super meaty ones that are loaded with salt and preservatives - for right now. Mother Hubbard type biscuits are awesome and don't upset stomachs.
Also I was wondering should I bring the puppy outside to roam around or should I let it stay inside because of its weak immune system as a puppy
That probably depends on where you live.
When I picked up Bertie, he and his brothers had just had a bath because they had been outside playing all morning.
And the way I raise puppies and keep my dogs... they go outside frequently. Not just for potty, but to get fresh air and get a chance to run around and play (with me out there with them). It keeps them from building up too much crazy energy.
Good luck, and have fun!