Roles are there to define what a user may or may not do within Lytho.
It is mandatory to link every new user to a role. Therefore roles need to be defined in advance. Read this article to learn how roles can be defined.
Lytho users can be given different roles depending on what they should, or should not be able to do. For each role a set of rules can be selected or left unselected. For instance, rules can give a user access to a module, rights to add/edit/delete assets or rights to manage settings.