Make my first triggers schedule an action at a certain time

[Crescenzo Cuomo]

Hello everybody,
I need support to create my first mysql triggers,
briefly explaining the situation I tell you:

I have an appointment table in the database,
my requirement is that every day at 20:00 the triggers identify all the appointments
who have given (equal to today's date) and been "IN PRODUCTION" appointment and moved to half
update all appointments the following day:

I tried to throw you down a bland attempt:

delimiter $$;

CREATE TRIGGER update_data
BEFORE UPDATE ON nomedb.appuntamenti
FOR EACH ROW
BEGIN
IF nomedb.data = CURRENT_DATE AND stato_pren = "LAVORAZIONE" THEN
SET nomedb.data = DATE_ADD(data, INTERVAL 1 DAY);
END $$

DELIMITER ;

I thank all of you in advance