FOSS gamedev and creative worlds

how can i add moderator in my server?

thanks in advance.

Go on the worlds/*world name*/auth.txt and add priviliges near the player name.

First, what privs do you want moderators to have? They should have at least ban and basic_privs, some admins give them fly and teleport too.
You can grant the privs to a player like this:

Replace "user" with the username of the moderator, of course.

Thanks!