Gnome Calls: How to configure

I would like to use Gnome Calls (or just Calls) (gnome-calls) as a softphone for making calls using SIP.

I used to use linphone, however Linphone crashes a lot and doesn’t look nice, so I thought why not try one of the alternatives.

The problem is that I have no clue how to setup the SIP account. There is nothing in the UI, there is nothing in Gnome Online Account and I can’t find documentation. Any suggestions?

I installed it too. I was thinking i could find the config files with whereis calls unfortunately no config files listed just the binary.

There are several tools for SIP, check sudo dnf info sip*

I saw a packages like sip-redirect, sipwitch, sipwitch-plugin-zeroconf, sipp
You might have to install and configure on the SIP protocol level, and call will recognize over the API it uses ?

I don’t know about this can yiu describe what it does and how to set it up
I didn’t find anything more usefull in internet.
Can i call other with this and how to use it.

Info from :

Make phone and SIP calls

Calls is a simple, elegant phone dialer and call handler for GNOME. It can be used with a cellular modem for plain old telephone calls as well as VoIP calls using the SIP protocol.

This plugin uses the libsofia-sip library for SIP signalling and GStreamer for media handling. It supports multiple SIP accounts and currently one active call at a time (subject to change).