Setting Roles

In the grid, check Granted against the server role listed in Role Name to assign this server login to be a member of selected server role. Multiple roles can be granted.

Note: Every SQL Server login belongs to the public server role. When a server principal has not been granted or denied specific permissions on a securable object, the user inherits the permissions granted to public on that object. Only assign public permissions on any object when you want the object to be available to all users.