Hello, @harmoniskissNOA,
Please see screenshot http://prntscr.com/fejw46
You can add [mc4wp_form]
shortcode to the Text editor (Theme Options->E-commerce->Promo Popup->Popup content).
As I see you updated woocommerce plugin to the latest version, but current theme v. 1.7.1 has compatibility issues with woocommerce 3.0.x.
You can download new theme version on ThemeForest https://themeforest.net/item/classico-responsive-woocommerce-wordpress-theme/11024192?s_rank=4. Log in to your account and go to the Downloads area. Then follow the documentation https://www.8theme.com/demo/docs/classico/#theme_installation_and_upgrade
Before uploading theme files delete “woocommerce” folder, which is located in wp-content/themes/classico/ to avoid problems with old files.
Don’t forget to create backup of your files and database before starting update process!
You need to enter your purchase code to activate the theme and skip Setup Wizard.
You can add links in Appearance > Widgets > Right/Left Side top bar area.
Regards,
Rose Tyler.