Google Workspace add-on - Calendar - custom

I'm starting a new module project for Google Workspace add-ons Calendar.

So I go through App-scripts to develop my module.

I have a few questions first:

• Is it possible to create a calendar when installing the module or do you have to go through existing calendars?
• The module aims to generate a custom checkbox in the event creation form on the Google Calendar web application. If the checbbox is checked during the validation of the event, we retrieve some information from the event to send it to a third party service.

Do you think this is possible?

Thanks.

• Few tests via App scripts. I can create events via App scripts in a calendar already created beforehand.