Can official organizations only make a tourney

Yes, of course they can, if they have the time to spare for tourneys.

Anyone can host a tourney. It's not restricted to just official members. Sometimes unofficial clans host tourneys and events to get their name out there before they apply to be official.

And how do you do that /motd thing (in all servers)

/motd message here

That sets the message for when people enter the server.

/desc blah blah

That sets the title of the room for others to see in the server list.

No like it tells every server

"are you bored want to earn tc? / jo rbbets"

^ something like that

http://forum.toribash.com/tori_broadcast.php

Located on the left hand side of the Torishop.