How do I set modifier on a member?

you suffix member declaration with 'is' and the modifier

class HasAMember
  def doSomething is protected
    pass

How do I set multiple modifier on a member?

you suffix member declaration with 'is' and a comma delimited list of modifier

class OverridesAMember
  def doSomething is protected, override
    pass

You can add attributes to classes and functions and variables also properties e.g. In GTK

class HasAnAttribute
  has TreeNode(listOnly=true)

  var name is String
      has TreeNodeValue(column=0)

  def doSomething is protected, override has STAThread
    pass

Usually we need to indent the code for the attribute