Can't create MySQL Trigger with several tables

I've got a database with 3 tables:

1. delivery
2. company
3. details

The company table has a column with ratings from 1 to 10 and if a rating is more than 5 we can understand that this company is reliable and in detail if the price is more than 1000 it is expensive detail.

Table delivery is connecting table for company and details Now I'm trying to create a trigger that will block Insert when somebody trying to add in table delivery expensive detail with an unreliable company, but I can't understand how to create Trigger using data from different tables.

I'm using MySQL

DELIMITER //
CREATE TRIGGER before_insert_1
BEFORE INSERT
ON delivery
FOR EACH ROW
IF company.rating < 5 AND detail.Det_Price > 1000 THEN
SIGNAL SQLSTATE '45000'
SET MESSAGE_TEXT = 'Unreliable company';
END IF //
DELIMITER ;