One requirement matters here: the bot's role must sit above the roles it hands out.

Open the module from its card or from the sidebar rail on any portal page. Settings save to the cloud and the bot picks them up within seconds. No restarts and no config files.
Discord only lets a bot grant roles below its own highest role. Drag the mimBo's role above your self-assign roles in Server Settings, then open the editor. If a click ever fails, the bot tells the member exactly that: it needs its role above the target and Manage Roles.
