All shoes have a break-in window, and trail shoes are no exception. The difference between breaking in a sneaker is that if you feel that they are killing your feet, you can simply head home and kick them off.
The biggest piece of advice that we can give you is that you should never, ever take a new pair of shoes out on the trail without testing them out first.
To break them in at home, make sure that you lace them up with the same sock you will wear on your next outdoor adventure. Wear them around the house, outside to check the mail, and to the grocery store to pick up trail snacks. If they rub your feet, simply keep wearing them until you would feel comfortable wearing them all day and night!