Tips on Customizing Post Grid

How to Hide Post Grid by PickPlugins Admin Menus

function plt_hide_post_grid_menus() {
	//Hide "Post Grid".
	remove_menu_page('edit.php?post_type=post_grid');
	//Hide "Post Grid → All Post Grid".
	remove_submenu_page('edit.php?post_type=post_grid', 'edit.php?post_type=post_grid');
	//Hide "Post Grid → Add New".
	remove_submenu_page('edit.php?post_type=post_grid', 'post-new.php?post_type=post_grid');
	//Hide "Post Grid → All Layouts".
	remove_submenu_page('edit.php?post_type=post_grid', 'edit.php?post_type=post_grid_layout');
	//Hide "Post Grid → Settings".
	remove_submenu_page('edit.php?post_type=post_grid', 'post-grid-settings');
	//Hide "Post Grid → Addons".
	remove_submenu_page('edit.php?post_type=post_grid', 'post-grid-addons');
	//Hide "Post Grid → Layouts library".
	remove_submenu_page('edit.php?post_type=post_grid', 'import_layouts');
}

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

Where do I put this code?

How to Hide Post Grid by PickPlugins Meta Boxes

function plt_hide_post_grid_metaboxes() {
	$screen = get_current_screen();
	if ( !$screen ) {
		return;
	}

	//Hide the "Post Grid - Post Options" meta box.
	remove_meta_box('post-grid-post-option', $screen->id, 'normal');
	//Hide the "Post Grid Options" meta box.
	remove_meta_box('post-grid', $screen->id, 'normal');
	//Hide the "Post Grid Info" meta box.
	remove_meta_box('post-grid-side', $screen->id, 'side');
	//Hide the "Layout data" meta box.
	remove_meta_box('post-grid-layout', $screen->id, 'normal');
}

add_action('add_meta_boxes', 'plt_hide_post_grid_metaboxes', 20);