The Classes + Events page in Debebe Theme https://debebe.vamtam.com/classes-events/ is built using WooCommerce products.
Each tab contains a particular template with products.
To begin, navigate to the Toolbar > Edit with Elementor > Classes - Item 1
Or go to Templates > Saved Templates > Classes - Item 1 > Edit with Elementor. Control the layout, conditions, rules and styles of the template.
Read more about the Elementor Templates
The date picker is part of the Extra Product Options plugin:
Read more about setting up the WooCommerce Shop & Archive pages