Well first you have to make a group with certain permissions before you can make any users, because you have to add users to a group when you make them. This can be done under
System > User Manager > "Group" tabWhen you get there, you set a group name and description, and assign permissions for what you want that group to be allowed access to. To get them to be able to login as you wanted with a name and pw, make sure at least the first 2 boxes are checked when making a group:
*Landing Page after Login,
*User Password. Any other boxes you check depend on what users in that group will be allowed to do. Choose 'save' at the bottom to make the group.
Now goto the user's tab and choose + to add a new user. Choose a username and password that they will login with, and the Full Name to better identify the user. Lastly, choose the group they will be in and click 'save'. Now you can login with that user.
Hope that's what you were asking, good luck!