Surface Pro 4

 I was easy to find the connection on my iPhone SE but I could not managed the same with my Surface Pro 4. Is there an app or is it through the Zwift web page.

Every time I try the webpage it give me an error when I know the Bluetooth is on. Any suggestions.

Hi there,

Zwift does not currently support native Bluetooth on PC. You will need to use the Zwift Mobile Link app through your smartphone if you plan to connect via bluetooth. The webpage is irrelevant to the use of bluetooth, so you wouldn’t need to log in there for any reason when you are trying to pair your devices before a ride. 

Please see our knowledge base article for more information about the Zwift Mobile Link
 - https://support.zwift.com/hc/en-us/articles/205055065-Zwift-Mobile-Link

If your trainer supports ANT+, you can connect to your SP4 with an ANT+ USB Dongle. I have an SP3 and use the Garmin ANT+ Dongle at the end of a 10’ USB extension cable which places the ANT+ USB receiver within a foot of my trainer and my bike cadence receiver. I use the Android Mobile app at the same time.