Thank you @heatherbell and @Fiber for your help!

admin > layout modules > product info > {install} > responsible bookmarks module installed and show on the product_info page but there is an error admin > layout modules > product info Notice: Undefined property: pi_responsible_social_bookmarks::$content_width in C:\xampp\htdocs\test\admin\modules_...

Thank you. @ecartz!

When the 'reviews' and 'reviews_description' tables are empty (there are no reviews), in the 'admin/reviews.php' page it shows no error, like this: Screen Shot 2022-02-12 at 4.56.45 PM.png If there are reviews in the 'reviews' and 'reviews_description' tables, in the 'admin/reviews.php' page it show...