Where to buy and general advice about Pokémon cards in Yokohama

So, my younger brother back home has gotten into Pokémon cards lately and asked me to buy some for him, as I live here. I know nothing about these things, and a Google search overwhelmed me NGL, so I decided to ask any kind resident that knows about them.

Do I need to go to a Pokémon center? Are there sold in like toy aisles or are there more like an adult game? Is there any type recommended for beginners (I know there's like a gazillion Pokémon "eras" so maybe cards are different)? Any questions I should ask my brother to clarify?

I'm completely ignorant about this and I'm grateful for any tips and advice!

by LittleDream210