Instructions
Access the Pokémon storage PC in any Pokémon Center. Withdraw your Charizard. If your Charizard is female, withdraw any other Pokémon that is of the "Monster" or "Dragon" type. Monster Pokémon are Bulbasaur, Charmander, Squirtle, Nidoran, Slowpoke, Cubone, Lickitung, Rhyhorn, Lapras, Snorlax, Chikorita, Totodile, Mareep, Ampharos, Larvitar, Treecko, Mudkip, Whismur, Aron, Tropius, Turtwig, Cranidos, Shieldon, Gible, Snover and Rhyperior or any of their evolutionary forms. Dragon Pokémon are Ekans, Horsea, Magikarp, Dratini, Kingdra, Swablu, Sevipar, Feebas, Bagon and Gible, or any of their evolutionary forms.
Withdraw a Ditto if your Charizard is male.
Visit the daycare center in your "Pokémon" game. In "Pokémon Gold" and "Silver," it is on Route 34. In "Ruby" and "Sapphire," it is on Route 117. In "FireRed" and "LeafGreen," it is on Four Island. In "Diamond" and "Pearl," it is in Solaceon Town. In "Black" and "White," it is on Route 3.
Talk to the old man that runs the daycare and leave your Charizard and the compatible Pokémon you have chosen in his care. Exit the daycare.
Take 256 steps. For every 256 steps you take, your Pokémon in the daycare may produce an egg. Return to the daycare center and talk to the old man. If he has no egg for you, exit the daycare center, take another 256 steps and return to ask the old man once again if he has an egg. Eventually, he will have an egg and give it to you.
Take 5,120 more steps. This is the amount of steps it requires to make your egg hatch. After the egg hatches, you will have a new Charmander in your possession. Check its gender in your Pokémon menu. If it is female, return to the daycare to receive another egg and try again.
Train your new baby Charmander until it reaches level 36 and evolves into a Charizard.