The first thing you should do when a new cat arrives in your home is to make sure that the litter box is in place and cleaned/filled. Take the cat out of the transportation cage and place it in the litter box. This ensures that the cat navigates from the litter box as its point of origin, and always knows where the litter box is and where to do its business.
A close second is to ensure the cat has access to clean water and food.
Let the cat explore its new home in its own pace.