The example you quoted from the docs only shows a simple example of how to create an email template. You may want to handle this in your plugin's install and uninstall methods so you can create the group and template when your plugin is installed rather than when accessing a controller, as the example illustrates. You can take a look at the Support Manager plugin source for working examples.
Set a name and description for the email template by defining a language file, admin_company_emails, containing them, in the following format:
File:
/plugins/myplugin/language/en_us/admin_company_emails.php
Contents:
<?php
$lang['AdminCompanyEmails.templates.action_name'] = "Email Template Name";
$lang['AdminCompanyEmails.templates.action_desc'] = "Email Template Description";
The "action" in the language term AdminCompanyEmails.templates.action_name should be the action of the email template group you created. For example, your group action is called MyPlugin.custom_action, so the language term would be
$lang['AdminCompanyEmails.templates.MyPlugin.custom_action_name'] = "Email Template Name";