Instructions
Enter Radio Tower and talk with the Grunt who is guarding the door and staircase. He will tell you that only those dressed as Team Rocket members are allowed entrance to the tower.
Head to Goldenrod Tunnel, which is in the center of the city, and travel to the northern part of the tunnel. You will see a Rocket Grunt recruiting for new members. Talk with him; he̵7;ll give you a Team Rocket uniform.
Head back to the tower. This time, the Grunt will allow you to enter; however, your rival will arrive and give you away. Win a battle against the Grunt. He will then run off to warn everyone that you are there.
Head up the stairs to navigate up the tower. Fight one of the Grunts on each floor of the tower until you reach the fifth and final floor.
Speak to the man on the fifth floor; he will tell you that he is the owner of the tower. He will eventually reveal that he is the Team Rocket Leader, known as Petrel, the Executive. He will have six Pokemon that you will need to defeat. Five of them are Koffings ̵2; level 30, Poison-type Pokemon, which you can defeat with Psychic- or Ground-type attacks. The final one is a Level 32 Weezing, which is an evolved Koffing and has the same weaknesses.