How do you get more than 1 Eevee on Pokemon leaf green?

(Note. Have to defeat pokemon league first and help Bill's friend to get the 2 gems)you can get more than one eevee, but you have to get one first, which is in the back of the pokemon mansion in Celadon City. After you get the eevee you go to Route 15 and walk around in the grass for a while, and with luck, you might find a ditto there and catch it. When you catch the ditto go to island 6 or 7 or 8 i forgot which and there will be another day care centre there and you put the ditto and eevee with them, come back in another day and they will give you an egg with your 2 pokemon. Hatch that egg and there will be an eevee inside. Working. I've done it myself