Pokémon HeartGold and SoulSilver/Gameplay

Catching Pokémon
After you've delivered the egg to Professor Elm and left ../New Bark Town/, you'll be given a tutorial on how to catch wild Pokémon by your friend. They'll show you that you should weaken the Pokémon until its HP is in the red or yellow, and then throw a Poké Ball. If you can, try giving the enemy a status, such as sleep, freeze, or paralysis. These will increase the odds of capturing it. Pokémon that have been caught at least three times and Pokémon acquired through trades will be easier to catch, as well. You cannot capture another trainer's Pokémon, and you cannot catch a Pokémon while in a double battle. After you've captured it, you'll have the option to nickname the Pokémon you catch. If you're party is full, the Pokémon will be transferred over to your in your most recent box.

The type of Poké Ball you use will also affect whether or not you're successful at catching a Pokémon.

Pokémon Centers
Located in every town and city, as well as various other places, Pokémon Centers are the ones responsible for keeping Pokémon fit. Whether it be from fighting or other causes, any injury is treatable there. Visiting a Pokémon Center will revive fainted Pokémon, restore your Pokémon's HP and PP, as well as cure any status (Pokérus excluded). The PC is also located in the Pokémon Center. The PC allows for players to store Pokémon that aren't currently in their party for use later, as well storing items, and checking Hall of Fame records. In the basement and second floor of the Pokémon Center, there are areas where you can use WiFi to communicate, but these features are covered in the Wifi section.