Empty landing page in language 2

Hi,

I have a website with static landing page in two languages: french (main one) and english. The problem is that the english flag on the french Menu is linked to this page: https://sebastien-aegerter.ch/en/ -> but this page is empty and I can’t add content because it’s not a page I’ve created. My question would be: is it possible to change the link of the flag and link to this address: https://sebastien-aegerter.ch/agenda/

The agenda page would then become the landing page for the english version.

My website: https://www.sebastien-aegerter.ch

Thanks a lot for your help ??
Alessandro