How do you get a point card in Pokemon platinum version?

You don't actually get a "point card" in Pokemon Platinum. It's likely you're thinking of the "Poketch".

Here's how to get a Poketch:

1. Beat the first gym leader: You'll receive the Poketch from Professor Rowan after you defeat Gardenia in Eterna City.

2. Use the Poketch: It's a wrist-mounted device with various apps, which you can unlock by finding new applications scattered around the world.

While there are no points to collect, the Poketch can be used to:

* Track your steps: Use the "Step Counter" app.

* Learn about Pokémon: The "Pokédex" app will help you study Pokémon.

* Check the time: Use the "Clock" app.

* Play minigames: The "Minigames" app offers different games to play, like "Puzzle."

There are many other apps to unlock as you progress through the game. Enjoy exploring your new Poketch!