Make sure your Android device is in Developer USB-debugging mode and select trust this computer if prompted.
Setting Developer USB debugging mode video(YouTube)1) Go to Settings and tap About device usually near bottom of list.
2) Tap the Build Number 7 times to become a developer. (prompt may keep a count for you)
3) A new Developer option will appear in Settings usually near About at bottom of list
4) Tap the USB debugging mode listed in Developer options and press OK in prompt.
1) My Nexus 7 tablet came up with problems when a ! sign was displayed next to it in Device Manager:
Right clicking Update drivers and Searching for Drivers on the Web did not find anything either!
2) So I Searched Google for "nexus 7 drivers windows 10" and found this download: latest_usb_driver_windows
I downloaded and unzipped it to the folder above. In Device Manager, Update Driver and Browse my computer and used the path to Downloads:
Downloads\latest_usb_driver_windows\usb_driver folder. Do not chose the i386 or amd64 folders. Windows will use android_winusb setup!
Now my Nexus 7 not only shows up, but it has its own Portable Devices category :
Android Device and Android Composite ADB Interface for debugging displays up top too then!
This is the first step for Android developers! Make sure Windows sees your device!
Now it also shows up in Android Studio after it is installed and the green Run arrow is clicked in your project:
QB Android Installation Procedure WIKI