Need Help to Start an Event

How can I start event just like (Mocomochi event or FlyFF Event - Spring 2020). Thank you.

Event.lua

Code:

---

AddEvent( "Mocomochi Event" )
--{
        SetTime( "2010-02-23 00:00", "2099-12-25 23:59" )
        SetSpawn( MONSTER, "MI_MOCOMOCHI1", 2000 )
--}

---

Change 2000 to how many you want spawned across the entire game.

Thank You.