Custom Module on the Activity Calendar

Good Morning everyone.

I want to ask if someone know how to create a custom activity types like calls, meetings and events. I want to display opportunities in the activity calendar so i tried to create a custom display (I tried to clone Events) but when i try to display it in the calendar, i got an unfinished page and the calendar do not display. Is there a clean way to create custom activity entities in SuiteCRM?

Thank you for reading this.