The server (I think) doesn't have to be syntazia, it can be others, but in this case is:
movim.syntazia.org
you will be greeted by a login screen or register, your account will be (ex: 4liv3@ syntazia.org)
The resource (obarun's actual server) is muc.syntazia.org
The board/room ... obarun@ muc.syntazia.org
Many web-browsers are xmpp capable, so you can just use the address to register and get in the 1st time, then choose a client to be configured for it.
Somewhere in your client menu you should have the ability to start/join a chat or research a for a chat. Just put the obarun@ muc.syntazia.org and you should see the obarun channel.
something like this (this is gajim client).