Answer
Give a newly arrived tarantula water and time to settle. Offer suitable prey once it has established a normal posture/retreat and there are no strong premoult signs.
After shipping
Travel can leave a spider defensive, inactive or uninterested in food. Move it into the prepared enclosure and minimise disturbance for the first few days.
Water first
Make sure the water dish is full. Hydration and a secure retreat matter more than forcing an immediate meal.
Check for premoult
If the spider refuses food, has a darkening abdomen, seals a retreat or shows other premoult behaviour, remove prey and wait.
First meal
Use an appropriately sized feeder and remove it if ignored. One refused meal after arrival is not unusual.