Here's a breakdown of the steps:
1. Complete the main story: You need to beat all eight gym leaders and collect all eight badges.
2. Reach the Pokemon League: After collecting all badges, you'll be able to enter the Pokemon League in Ever Grande City.
3. Defeat the Elite Four: You'll face four powerful trainers in a row: Sidney, Phoebe, Glacia, and Drake. Each Elite Four member has a specific team composition and challenges you'll need to overcome.
4. Challenge the Champion: Once you defeat the Elite Four, you'll face the Champion, Wallace. He's a tough opponent with a strong team of water-type Pokemon.
5. Victory and the Hall of Fame: After defeating Wallace, you'll be declared the champion! You'll then be inducted into the Hall of Fame, where you can see your Pokemon and victory displayed.
Remember: Once you enter the Hall of Fame, your game data is saved, and you'll be able to continue your adventure with your Pokemon. You can even start a new game from the beginning, but you'll be able to keep your Hall of Fame entry!