How have you catch Entei in Pokemon FireRed?

You can't catch Entei in Pokemon FireRed. Entei is a Legendary Pokémon that appears in Pokemon Gold, Silver, and Crystal, not FireRed.

You can, however, catch other Legendary Pokémon in FireRed like:

* Articuno, Zapdos, and Moltres: These Legendary Birds can be found in the Victory Road after you defeat the Elite Four.

* Mewtwo: This powerful Psychic-type Pokémon can be found in Cerulean Cave after you defeat the Elite Four.

* Raikou, Entei, and Suicune: These Legendary Beasts are not available in FireRed. They are only available in Pokemon Gold, Silver, and Crystal.

If you're looking to catch Entei, you'll need to play Pokemon Gold, Silver, or Crystal.