Acer Aspire S3-391 - Manual (Page 87)

86 - Using a Bluetooth connection
Note: Some devices using older versions of the Bluetooth technology
require both devices to enter a PIN. In the case of one of the devices
not having any inputs (as in a headset), the passcode is hardcoded
into the device (usually "0000" or "1234"). Consult your device’s user
manual for more information.
Your device will show up in the list of devices if it was successfully paired.
Open the Control Panel and under Hardware and Sound click on View
devices and printers. Right cilck on your device and select Advanced
Operations > Connect to operation window.