Your kitten has left the security with his siblings and mother and naturally feels a little lost in his new environment. Let the kitten explore his new home in peace and quiet, preferably one room at a time. Do not forget to repeatedly show it where the toilet, food & water are :)
A good room to start letting the kitten explore is, for example, the bedroom with dim light, a room where they are quiet and there are no children or other animals. Where it can calm down after the car journey, catch its breath and return to a curious mindset.
If you have cats / dogs since before, there's a really good technique to ensure that they get along, do not stress but let the introduction take days instead of hours!
Read more here: The Do's and Don'ts of Introducing Cats