Wordpress into the background, to open the template functions.php
Inside adding this code:
if ( function_exists('register_sidebar') )
register_sidebar(array(
'before_widget' => '<div class="sidebox"> ',
'after_widget' => '</div>',
'before_title' => '<h2>',
'after_title' => '</h2>',
));
Reference: https://jingyan.baidu.com/article/8ebacdf0c02b5c49f65cd53a.html