How to enable the SIP gateway

Can someone help me out please, because I don’t know how to figure this out by myself.
It seems to be possible to use the Pade plugin for Openfire to connect with a webcam on a webpage.
I am working in a test environment with an admin (Pidgin) and a test user (Spark), both are on LAN clients, so I don’t need to worry about ports.
Both accounts can login to a chatroom and communicate.

The next step is to use the Pade plugin to be able to use a webcam.
I am unable to login the test user in the login screen (no error message).
According to a post I read, it’s required to install Pade on the server and create a certificate for it.
According to the Pade manual I only need to enable the SIP gateway, a new user called jigasi will be created and it will join a global conference called jigasi with the focus user focus.

Before things get even more complicated, this is my question:

How do I enable the SIP gateway (no explanation of this is in the manual or online … ?!?

Please advice.

I was able to solve my problems by following the WikiSuite, but this will not be a solution for everyone.
The reasons are because I use a ClearOS box and a Let’s Encrypt certificate.
This limits me to Openfire 4.2.3, but AFAIK I still have all the functionality I require.