Warning message display when try to log in to my website

I have not take care of my site for couple months. Recently, I want to update my WordPress and Themes. However, when I try to login https://www.beatyourbuy/wp-admin. It give me below message. First of all, I am not a IT expert, have limited knowledge of IT. Would really appreciate someone can help me about this.

The error message show as below, forgive my poor English.

Warning: include(/home/fredyu/public_html/wp-content/plugins/woocommerce-checkout-manager/includes/classes/main.php): failed to open stream: No such file or directory in /home/fredyu/public_html/wp-content/plugins/woocommerce-checkout-manager/woocommerce-checkout-manager.php on line 15

Warning: include(): Failed opening ‘/home/fredyu/public_html/wp-content/plugins/woocommerce-checkout-manager/includes/templates/functions/required/shipping_required.php’ for inclusion (include_path=’.:/opt/alt/php55/usr/share/pear:/opt/alt/php55/usr/share/php’) in /home/fredyu/public_html/wp-content/plugins/woocommerce-checkout-manager/woocommerce-checkout-manager.php on line 27

Warning: include(/home/fredyu/public_html/wp-content/plugins/woocommerce-checkout-manager/includes/templates/functions/woocm_editing_wrapper.php): failed to open stream: No such file or directory in /home/fredyu/public_html/wp-content/plugins/woocommerce-checkout-manager/woocommerce-checkout-manager.php on line 28

…….(there are more when you go to page https://www.beatyourbuy.com)

Fatal error: Call to undefined function wccs_positioning() in /home/fredyu/public_html/wp-content/plugins/woocommerce-checkout-manager/woocommerce-checkout-manager.php on line 75

Thanks again for your generous help.

Fred