In your server options there are a list of 'staffguilds'. Add any guilds into the list if they are not already in there.
In order to create guilds you can create a text file named 'guildGuildName.txt' and add members to it using this format:
Use line breaks to separate members.
For example, to accomplish an Owner tag I would make a text file called guildOwner.txt with this text in it:
After you've created the text file, upload it to levels/guilds/ and set your nickname.
Edit: Oops, Chompy got here first, hope this helps anyways.