How do you get to the Saffron city Gym leader?

You have to go in Silph co in Saffron city and on the 11th floor you will see Gary and another person. Defeat Gary and talk to the another person and he will give you Lapras and just to tell you make sure have the card key.(You'll get it from a Team Rocket Member in the 3rd floor) After you beat Gary and get Lapras go straight down then up use the card key for all 2 of the doors then you will see Giovanni talking to the president. Then defeat Giovanni and the president will give you the master ball. Now you can go in Saffron city gym.