How to create a calender and events to it? [HELP]

I’m making an online calender that notifies the end user when a new event is posted from the admin panel.
I’m trying to tint the color of the dates with active events so that the user can tap on it to reveal more details about the event.

I’m not sure how to proceed with this.

For context, I used Mevi’s tutrial on YT to create my initial calender layout