In order to Administrate Project Zomboid with Clanforge:
Project Zomboid creates an default Admin user with a persistent password upon startup.
Username is admin.
This password can be found at:
Clanforge > Your Server > Edit Profile > Admin Password
Admin username cannot be changed via Clanforge at this time.
Admin password is set using the password you have within Clanforge upon Initial Start/World Creation.
In order to change the admin password you will need to set your admin password within Clanforge and then create a new world.