also I See there is a new module to make changes on one installation of ispconfig from another installation, how does this work and how is it configured as it will not allow me to make changes?
there is no such module implemented yet, it will get implemented in one of the next releases.
is there a method of syncing these (like an authenication or something)
There are several methods:
1) Use zone transfers like bind does it.
2) Connect the slave dns server to the same mysql database then the master.
3) use mysql database replication.
4) Wait for the next major ispconfig release when ispconfig will introduduce replication fo servers.