https://tr.wordpress.org/plugins/wp-custom-widget-area/

https://tr.wordpress.org/plugins/so-widgets-bundle/

https://www.wpbeginner.com/beginners-guide/how-to-add-and-use-widgets-in-wordpress/

https://buckleupstudios.com/add-a-new-widget-area-to-a-wordpress-theme/

https://www.wpbeginner.com/wp-tutorials/how-to-create-a-custom-wordpress-widget/