TypoScript

lib.myPlugin  = USER
lib.myPlugin {
  userFunc = TYPO3\CMS\Extbase\Core\Bootstrap->run
  extensionName = MyExtensionName
  pluginName = MyPluginName
  vendorName = Vendor
  controller = MyController
  action = myAction
  switchableControllerActions {
    MyController{
      1 = myAction
    }
  }
}