How to Hide CMXR — Canvas Motion Backgrounds Admin Menus

function plt_hide_cmxr_canvas_motion_backgrounds_menus() {
	//Hide "CMXR".
	remove_menu_page('cmxr');
	//Hide "CMXR → Animations".
	remove_submenu_page('cmxr', 'cmxr');
	//Hide "CMXR → New Animation".
	remove_submenu_page('cmxr', 'cmxr-new');
	//Hide "CMXR → Settings".
	remove_submenu_page('cmxr', 'cmxr-settings');
	//Hide "CMXR → Debug".
	remove_submenu_page('cmxr', 'cmxr-debug');
	//Hide "CMXR → ExploreXR".
	remove_submenu_page('cmxr', 'cmxr-explorexr');
}

add_action('admin_menu', 'plt_hide_cmxr_canvas_motion_backgrounds_menus', 11);

Where do I put this code?