Explicit Web Proxy-can't find the source interface web-proxy

Hi good day!

I am new using Fortigate, and i am facing some issues applying web proxy.

I had tried to follow the guide from docs foritos-handbook-40-mr3 and the video This is what I should done> enable the explicit web proxy , in internal interface check Enable Explicit Web Proxy > set up policy : source interface: web-proxy, dest interface: wan1 (connect to internet), source and dest address use all, service: web proxy (default), action accept.

But i get stuck when I tried to set up the policy because I cannot find the "source interface: web-proxy"

My question is, the web-proxy interface is automatically created or I have to create. Because in the videos i did not see any step were they create the ''interface web-proxy''.

My fortigate model is FG-200D

Best Regards

Braulio Castigo