If you added the new user correctly, this is what you see:
myaccount@trisquel:~$ sudo adduser newuser
[sudo] password for myaccount:
Adding user `newuser' ...
Adding new group `newuser' (1002) ...
Adding new user `newuser' (1002) with group `newuser' ...
Creating home directory `/home/newuser' ...
Copying files from `/etc/skel' ...
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
Changing the user information for newuser
Enter the new value, or press ENTER for the default
Full Name []:
Room Number []:
Work Phone []:
Home Phone []:
Other []:
Is the information correct? [Y/n] y
myaccount@trisquel:~$
After this the new user 'newuser' can be selected at the login screen. It
shows up.
