Create a new user:
replace username with the user that you want to create.
Give your user a password so that they can log in:
You will be prompted to type in the password twice to confirm it. Now your new user is set up and ready for use! You can now log in as that user, using the password that you set up.
Create a new group:
List users in group:
getent group groupname
Add a user to a group:
usermod -a -G groupname username
gpasswd -a username groupname
or add a user to multiple groups:
usermod -a -G group1,group2,group3 exampleusername
Delete user from group:
gpasswd -d username groupname