Connecting Xiaomi Redmi 3s to PC
It's very easy. Follow steps

Install Google USB Driver From SDK Manager.
Now Open Device Manager.
Check for your device in Other Devices or Portable Devices
Right-click and click on Update Driver Software -&gt; Browse my computer for driver software -&gt; Let me pick from a list of device drivers... -&gt; Have Disk -&gt; Browse -&gt; (C:\Users\Your user\AppData\Local\Android\sdk\extras\google\usb_driver) -&gt; select android_winusb -&gt; Now update your driver.

It should work perfectly.