Instructions
Select the "Mystery Gift" option from the main menu of ̶0;Pokemon HeartGold̶1; and choose "Receive Gift."
Download the Yellow Forest via Nintendo WFC. You will need a local Wi-Fi signal to download the Pokewalker level.
Enter any Poke Mart and talk to the deliveryman standing beside the counter to receive the map to Yellow Forest. Many types of Pikachu live in this Pokewalker course. Save the game and turn off the Nintendo DS.
Turn on the Nintendo DS and choose the Connect to Pokewalker option from the main menu. Choose one of your Pokemon to send to the Pokewalker. Grass- and Ground-type Pokemon will fare better against the horde of Electrical Pikachu.
Choose the Yellow Forest level and connect the Pokewalker. Surfing Pikachu start to appear after you save 9,500 steps.
Use ten Watts to capture the Surfing Pikachu. Every 200 steps you take will give you one Watt. Lower the Surfing Pikachu̵7;s health meter before you try to capture it.