Android Studio doesn't recognize my device

Question

Here is the problem. I want to run my Android Studio apps on my device (Samsung Galaxy Ace 2). But nothing works for me. Tell me what I\'ve missed:

1) USB debugging

Answer 1

I am sorry that i bothered you all. The problem was my device is cloned in different places in device manager. It was gone when I tried to update driver for my phone in "Other devices" list, and before i have been updating it in wrong sections. Thank you all.