This guide will let you know how to talk to Miguel Madrazo in GTA V.
First, you will get a text from Miguel Madrazo to help him. You have to go to the music locker, and you need to have a penthouse above the casino to access the music locker nightclub through the elevator in the casino.
You can also enter from the north side of the diamond casino and resort entrance. To go inside the nightclub, you need to pay a hundred and fifty dollars at the front desk, as shown in the image below.
Once inside the nightclub, you need to go downstairs and head to the VIP area. The staff will stop you when you get there, and a cutscene will start, as shown in the image below.
After the cutscene, you need to purchase the Kosatka Submarine from the war stock cache and carry, worth two million dollars, to do the Cayo Perico Heist questline.