On pick up day remember to bring paper towels, a garbage bag and something to lay across your lap or back seat. Some golden retriever puppies get car sick. Keep the car cool and don't wrap the puppy in a blanket as they tend to run hot and this doesn't help with car sickness. I recommend you sit in the backseat so the puppy has a chance to move off of your lap to cool down.
Once home take your puppy on a leash to your back yard and let the puppy sniff around, hopefully they will do their business before going into your house.
For the next week keep your puppy confined to the area of the house where the back door is and the crate/play area. This should be in a room that you like to hang out in such as the family room/kitchen. It will be easier for you to get the puppy out the door quickly to do its business and puppies don't like to be alone. Especially when they leave their littermates, me and everything they know. This will give your puppy more stability and confidence. Don't overdue it this week with visitors and definately no other dogs outside of your house. Remember this a big step for a puppy and a very stressful event. Let them settle in and get comfortable with your family and their new surroundings. You should sleep next to your puppy at night for the first week or you might not get alot of sleep. If your puppy fusses in the night just put your hand next to the crate and say "shhhh" quietly. This will reassure your puppy that someone is there. If your puppy really fusses and can't settle they might have to go to the bathroom in which case quietly get up, pick your puppy up and carry them outside to do their business. Remain calm and quiet and then bring your puppy back in and put back in the crate and go back to sleep.
Get your puppy into a routine this helps lessen stress as the puppy gets to know what is expected.
I f you have a dog at home:
Please take your older dog out on a leash to your front yard to introduce them to the puppy. Put the puppy on the ground on leash and let them sniff each other, get to know each other a little bit. It is on more neutral ground so your older dog should be less protective and then walk them into the house together. Always be watching your older dog for signs of stress or aggression. Puppies don't read warning signs well.