Hi. Can this CMS handle users groups like joomla?
Does it have the ability to make public or hidden certain pages or content per user group like joomla?

It does via the ‘login’ plugin: combined with groups and permissions

And how we add user?

for each user theres a yaml file under user/accounts. If you want to add a user simply add a new file with the username and the yaml parameters like

fullname: 'Admin'
title: Administrator
state: enabled
    login: 'true'
    super: 'true'
    login: 'true'
language: de

Here you are able to set your access aswell.

Also see Adding and Managing Users

can a user register from front end site?

and what will be the password if i creatte a new user through yaml file?

ok found out.
the big question is if we are able to have login area and when logged in new items shown like Joomla