Plugin starter boilerplate

Inside the core plugin file (not necessarily index.php or plugin-name.php):

<?php
/*
Plugin Name: some name
Version: 0.1
Author URI: https://justicebeard.com/
*/

class MyUniquePluginDescriptorClassName {
	function __construct(){
		add_action('admin_menu', array($this,'dashboardInfo'));
		add_action('admin_init', array($this,'customSettings'));
	}

	function customSettings(){
		register_setting();
	}

	function dashboardInfo(){
		add_options_page(
			'HTML Title', 'Settings Text', 'manage_options', 'plugin-slug', array($this,'dashboardOutput'))
			// arguments: 
			// https://developer.wordpress.org/reference/functions/add_options_page/
		);
	}

	function dashboardOutput(){
		?>
		<div class="my-plugin-dashboard">
		<h1>Settings or whatever</h1>
			content to be displayed on the dashboard settings page
		</div>
		<?php
	}
}
$myUniquePluginDescriptorClassName = new MyUniquePluginDescriptorClassName();