Since this is a mobile game, the player's phone will vibrate once a Pokémon is found nearby. Once they have encountered a Pokémon, they can use the phone's touch screen to catch it with a Poké Ball. Poké Balls and other special items can be found at PokéStops located at interesting places such as public art installations, historical markers and monuments.
As for the gameplay, players are encouraged to join one of three teams and engage in Gym battles with other teams. Once they are part of a team, players have the ability to assign their Pokémon to empty Gyms. These Gyms can be found at real world locations, and because only one Pokémon per player can be placed at a given Gym, team members will need to work together to strengthen the Gym's defense. A Gym claimed by one team can be challenged by the other two teams.
Pokémon GO will be available for the iOS and Android later this year via the App Store and Google Play. But if you are living in Japan, you can play the game early via a limited test rest run of the game while it is still in development.