"Dans" and "en" have the same meaning, but it's different depending on how you use it. If your saying "il m'attend dans la pizzeria" which translates to "he's waiting for me in the pizza shop." Au can also mean "at" but when your talking about where someone lives, it's almost always going to be "en." If you were saying "my uncle lives at the japan" it would be "au." Hope this helped! <3
