Instructions
Tune your PokeGear radio to the "Pokemon March" on any Wednesday. On Wednesdays, the station broadcasts the "Hoenn Sound" show, allowing you to catch Hoenn type Pokemon.
Visit a location where Minun is encountered. Minun is found at any of the following maps: National Park and Routes 1, 2, 3, 4, 5, 7, 8, 11, 14, 16, 17, 18, 29, 33, 36, 37, 38, 39, 46 and 48.
Engage in battles until you fight against Minun.
Use a Pokeball to catch Minun. After catching Minun, he is added to your list of Pokemon.