Here will add users with home dirs
Create a new dir on mounts, rights on the root will be exclusive to root
mkdir /mnt/data/homes
chmod 664 /mnt/data/homes
Create a new user and set its password, this will be the main user
useradd -m -d /mnt/data/homes/main main
passwd main
Create a new user and set its password, this will be the user for services stuffs
useradd services
passwd services
And a group for administrators, services and users
groupadd administrators
groupadd users
groupadd services
Root of course will be part of everything
usermod -a -G administrators root
usermod -a -G services root
usermod -a -G users root
Services will be administrator
usermod -a -G services services
usermod -a -G administrators services
Main will be user and admin
usermod -a -G administrators main
usermod -a -G users main
Create a generic user we will call it johnd (John Doe :P )
useradd -m -d /mnt/data/homes/johnd johnd
passwd johnd
Johnd will be a simple user
usermod -a -G users johnd