In order to follow these steps, the Field UI module must be installed. You'll need the Comment module's <em>@comment_permissions_link</em> permission, in order to change comment settings for a comment field. You'll also need to have the appropriate permission for adding fields to the entity type or subtype that the comments are attached to. For example, to add a comment field to content items provided by the Node module, you would need the Node module's <em>Administer content types</em> permission.