Make a Link list and Submenu

Example:

1. in yourmodule.links.menu.yml

yourmodule.test:

  title: Test

  parent: system.admin_config_development

  route_name: yourmodule.test

yourmodule.test.one:

  title: Test1

  parent: yourmodule.test

  route_name: yourmodule.test.one

yourmodule.test.two:

  title: Test2

  parent: yourmodule.test

  route_name: yourmodule.test.two

2. in yourmodule.routing.yml

yourmodule.test:

  path: '/admin/yourmodule/test'

  defaults:

    _controller: '\Drupal\system\Controller\SystemController::systemAdminMenuBlockPage'

    _title: 'Test'

  requirements:

    _permission: 'access administration pages'

    

yourmodule.test.one:

  path: '/admin/myx/myx_newsreader/crawl/readers'

  defaults:

    _controller: '\Drupal\yourmodule\Controller\Test::one'

    _title: 'One'

  requirements:

    _permission: 'access administration pages'



yourmodule.test.two:

  path: '/admin/myx/myx_newsreader/crawl/readers'

  defaults:

    _controller: '\Drupal\yourmodule\Controller\Test::two'

    _title: 'Two'

  requirements:

    _permission: 'access administration pages'

Example : Add item to site main menu

mymudule.teselink:

  title: Test

  menu_name: main

  route_name: mymudule.teselink